C.R.S. § 30-6-100.3 Definitions
30-6-100.3. Definitions. As used in this article, unless the context otherwise requires, "county" means any county or city and county.
Location, Change, and Settlement of Boundaries
C.R.S. tit. 30, art. 6
in effectC.R.S. § 30-6-101 Survey of boundaries - arbitration
30-6-101. Survey of boundaries - arbitration. Wherever the boundary lines of any county are so indefinite as to make it impossible to determine where such lines are, and when a portion of territory by reason of such indefinite description is claimed by two counties, the board of county commissioners of each county so claiming said territory is authorized to have a survey made to define the boundaries. If it occurs that either county is dissatisfied with the boundary line as thus determined, it may be entitled to require of the other an arbitration for the settlement of the matter, from which arbitration there shall be no appeal, and the decision shall be final.
C.R.S. § 30-6-102 Board of arbitration
30-6-102. Board of arbitration. When such arbitration is required, the board of county commissioners of each county shall choose one person from their county, and such persons shall select a third person who shall not be a resident of either county, and such three persons so chosen shall constitute a board of arbitration for the purposes mentioned in section 30-6-101.
C.R.S. § 30-6-103 Arbitration - agreements - oaths - expenses
30-6-103. Arbitration - agreements - oaths - expenses. All counties, before entering into such arbitration by their boards of county commissioners, shall sign such agreements as required by law concerning arbitrations, and the board of arbitrators, before acting in such capacity, shall take such oath as prescribed by law. The expense of survey and arbitration shall be equally borne by each county, to be paid out of the county general fund.
C.R.S. § 30-6-104 Boundaries not changed
30-6-104. Boundaries not changed. Nothing in sections 30-6-101 to 30-6-103 shall be construed to authorize a change of county lines.
C.R.S. § 30-6-105 Annexation - petition - notice to voters
30-6-105. Annexation - petition - notice to voters. When a majority of the taxpaying electors residing in that portion of the territory of any county proposed to be stricken off and annexed to an adjoining county shall petition the board of county commissioners of the county in which such territory is situate to have such portion stricken off and annexed to the adjoining county, giving the area and general boundaries of such territory by natural objects and monuments as near as may be, and shall deposit with such board of county commissioners an amount of money sufficient to pay the expenses of the surveying and platting of such territory, it is the duty of the said commissioners to have such territory surveyed and platted in a suitable manner and to cause to be submitted to the registered electors of such county at the general election next after the filing of such petition and plat with them the question of whether such portion of the territory of their county shall be so stricken off. The board of county commissioners shall also require the county clerk and recorder, in giving the notice required by law of the general election then next ensuing, to insert therein a notice to said registered electors that the question of striking off such territory from their county, particularly describing such territory by metes and bounds as shown by said survey, will be submitted to them for their approval or rejection and that they should designate on their ballots their approval thereof, which shall be expressed by the words "for the new county line", or their dissent thereto, expressed by the words "against the new county line". The board of county commissioners of the county to which such territory has been annexed may, in their discretion, pay the necessary expenses of such survey and plat by warrant on the treasury as in other cases.
C.R.S. § 30-6-106 Annexation - adjoining county
30-6-106. Annexation - adjoining county. Upon the receipt of the said petition and deposit by the board of county commissioners, they shall immediately give notice of the fact to the board of county commissioners of the adjoining county to which the petitioners desire said territory should be annexed, and the board of county commissioners of the adjoining county shall, upon receipt of the same, require the county clerk of that county, in giving notice of the next general election, to notify the electors of that county of the proposed annexation, particularly setting forth by metes and bounds in said notice the description of the said territory, that the question of such annexation will be submitted to them at said election, and that said electors shall designate on their ballots their dissent from or agreement thereto, which dissent or agreement shall be expressed as is provided in section 30-6-105.
C.R.S. § 30-6-107 Annexation - election result - proclamation
30-6-107. Annexation - election result - proclamation. When the votes cast at the annexation election have been duly canvassed, the county clerk of each of said counties shall transmit the result of said election, as to this question, along with the other returns, to the secretary of state, and if such canvass shows that a majority of the votes cast at said election in each of the said counties was in favor of the question submitted in the respective counties mentioned in section 30-6-106, the secretary of state shall immediately make proclamation thereof, setting forth a description of said territory, as it is described in said notice, plat, and survey, and that by virtue of such majority vote in said counties such territory has been stricken off from the one county, naming it, and annexed to the other county, naming it.
C.R.S. § 30-6-108 County clerk and recorders to record
30-6-108. County clerk and recorders to record. It is the duty of the county clerk and recorders of the said counties to record at length said proclamation of the secretary of state, together with said survey and plat, in the deed records of his county, and thereafter the county line so established shall be the lawfully constituted line between said counties, and the said territory so annexed to such county shall be subject to the jurisdiction of the county to which it has been so added, and shall be a part and parcel thereof.
C.R.S. § 30-6-109 Liabilities of annexed territory
30-6-109. Liabilities of annexed territory. The territory so stricken off from any county and annexed to the adjoining county shall be held to pay its ratable proportion of all then existing liabilities of the county from which it has been taken. Such ratable proportion of liabilities, as soon as the proclamation has been made, shall be fixed by the board of county commissioners of the county from which it is taken, and certified to the board of county commissioners of the county of which it becomes a part; and said board of county commissioners of the last mentioned county shall cause a special tax to be levied upon the property subject to taxation in such annexed territory for one, two, or three years, until such ratable proportion has been fully collected and paid, and the money, when collected, shall be refunded to the county from which the territory has been taken.
C.R.S. § 30-6-109.5 Annexation - county airports - agreements between governing bodies - approval
30-6-109.5. Annexation - county airports - agreements between governing bodies - approval. (1) Any provision of this article to the contrary notwithstanding, the territory of one county may be stricken off and annexed to an adjoining county, whether such territory is contiguous to such adjoining county or not, for the purpose of building and operating a major air carrier airport if the annexing county has a population of more than four hundred thousand and the boards of county commissioners of the two counties enter into an agreement for such annexation and the annexation agreement is subsequently ratified pursuant to the provisions of this section.
(2) Any such annexation agreement shall include, at a minimum:
(a) A description of the boundaries of the territory to be stricken off and annexed;
(b) A provision for the reversion of such territory to the county from which it is to be stricken off if the purposes of the annexation are not achieved;
(c) A provision that any consideration paid by the annexing county go to or for the benefit of the county and any school district from which the annexed territory is to be stricken off; and
(d) A provision designating either the next general election or a special election on a date certain as the ratification election for the proposed annexation agreement.
(3) In order to enter into such an agreement for the striking off and annexation of territory, each board of county commissioners shall be required to approve the agreement by a majority vote at a regular board meeting after not less than seven days' notice to the public and the opportunity for oral and written public comment on the agreement. Such notice shall be published in at least one newspaper of general circulation in the county or counties involved.
(4) After approval of the annexation agreement pursuant to subsection (3) of this section, the board of county commissioners of the county from which the territory is proposed to be stricken off shall submit such proposed annexation agreement to the registered electors of such county, pursuant to section 3 of article XIV of the state constitution, at the next general election or at a special election. Such election shall be governed by the provisions of the "Uniform Election Code of 1992", articles 1 to 13 of title 1, C.R.S., and shall be paid for by the county in which it is held.
(5) Failure of the registered electors to ratify the annexation agreement by majority vote shall defeat the proposed annexation, and the territory shall not be stricken off. The agreement shall be null and void.
C.R.S. § 30-6-109.7 Minor boundary adjustments
30-6-109.7. Minor boundary adjustments. (1) (a) The general assembly hereby finds and declares that:
(I) The existence of certain irregular and irrational boundaries between portions of the city and county of Denver and the neighboring counties of Adams, Arapahoe, and Jefferson has resulted in confusion and inefficiency in the delivery of public services, including police, fire, and emergency medical services, to properties on or near such boundaries; and
(II) Such irregular boundaries jeopardize the ability of landowners to utilize and develop their property and impose increased costs and service delays when those landowners seek development approval.
(b) The general assembly further finds and declares that it is the purpose of this section to:
(I) Create a statutory mechanism, permitted by section 3 of article XIV of the Colorado constitution, that provides landowners with a limited means by which such irregular and irrational boundaries may be corrected for territory located in the city and county of Denver and in the counties of Adams, Arapahoe, and Jefferson;
(II) Limit the minor boundary adjustments under this section to no more than fifty acres per adjustment and to no more than two hundred fifty acres for each such county; and
(III) Permit a minor county boundary adjustment only if such adjustment is requested by one hundred percent of the landowners of property within the territory that is subject to such adjustment and only after the consent of all affected counties, municipalities, and school districts has been obtained.
(2) Any provision of this article to the contrary notwithstanding, a portion of the territory of one county may be stricken off and added to an adjoining county without an election pursuant to the procedure contained in this section.
(3) (a) A petition initiating a minor boundary adjustment that is signed by one hundred percent of the landowners of the territory of a county proposed to be stricken off may be submitted to the board of county commissioners in which such territory is situate. The petition shall include a map, survey, and legal description giving the area and general boundaries of such territory.
(b) Upon receipt of the petition, the board of county commissioners in which such territory is situate shall conduct a hearing on the petition after not less than thirty days' notice to the public and allow the opportunity for oral and written comment on the petition. Such notice shall be published in at least one newspaper of general circulation in such territory. All owners of real property in the territory and any special district organized pursuant to title 32, C.R.S., that serves the territory are to be notified of such hearing by first-class mail not less than ten days and not more than thirty days before the hearing.
(c) Following such hearing, the board of county commissioners in which such territory is situate shall act by resolution to approve or deny the minor boundary adjustment initiated by the petition. In the event the minor boundary adjustment is denied, no further action shall be taken.
(d) As used in this subsection (3), "landowner" means the owner in fee of any undivided interest in a given parcel of land that is within the boundaries of the territory of the county proposed to be stricken off. If the mineral estate has been severed, the landowner is the owner in fee of an undivided interest in the surface estate and not the owner in fee of an undivided interest in the mineral estate.
(4) No resolution approving a boundary adjustment shall be adopted or effective pursuant to this section unless:
(a) The territory to be stricken off and added to an adjoining county is contiguous to such adjoining county;
(b) The total area of the territory to be stricken off and added to an adjoining county does not exceed fifty acres;
er in fee of an undivided interest in the mineral estate.
(4) No resolution approving a boundary adjustment shall be adopted or effective pursuant to this section unless:
(a) The territory to be stricken off and added to an adjoining county is contiguous to such adjoining county;
(b) The total area of the territory to be stricken off and added to an adjoining county does not exceed fifty acres;
(c) Both the county from which such territory is to be stricken off and the adjoining county to which such territory is to be added are represented on the boundary control commission established by section 1 of article XX of the Colorado constitution and the governing bodies of such counties have consented by resolution to the adjustment;
(d) As to any county boundary adjustment under this section which will result in the detachment of area from any school district and the attachment of the same to another school district, the board of directors of the school district to which such area will be attached and the board of directors of the school district from which such area will be detached have consented by resolution to such adjustment;
(e) The governing body of any municipality having incorporated territory contiguous to or contained within any portion of the territory to be stricken off has consented, by ordinance or resolution, to such adjustment.
(5) If a minor boundary adjustment is approved pursuant to this section, the board of county commissioners of the county from which such territory is to be stricken off shall negotiate an intergovernmental agreement with the adjoining county to which such territory is to be added. The intergovernmental agreement shall set forth the terms adjusting the boundary of each county and shall include, but not be limited to, the following:
(a) A description of the purpose of the minor boundary adjustment and of the petition initiating such adjustment;
(b) A provision specifying that obligations that are in any way secured by property taxes or other revenue streams from the territory to be stricken off shall be paid as provided in section 30-6-109.
(6) Upon approval by both counties of an intergovernmental agreement described in subsection (5) of this section, the board of county commissioners of each county that is a party to the agreement shall adopt a resolution approving the minor boundary adjustment. A copy of each resolution shall be recorded in the deed records of each county pursuant to section 30-6-108. Effective upon such recordation, the new county boundary so established shall be the lawfully constituted line between each county, and the territory stricken off from one county and added to the adjoining county shall be subject to the jurisdiction of such adjoining county and a part and parcel of the area of such adjoining county; except that the effective date of such new boundary for the purpose of general taxation shall be on and after the next January 1.
(7) Not more than two hundred fifty acres may be stricken from or added to any county pursuant to the provisions of this section.
(8) Except as provided by subsection (8.5) of this section, no territory of a county that contains an occupied residential unit may be stricken off and added to an adjoining county pursuant to this section. As used in this subsection (8), "occupied residential unit" means a building, or that portion of a building, designed for use predominantly as a place of residency by a person, a family, or families.
(8.5) Subsections (3) and (8) of this section shall not apply to a minor boundary adjustment if the county to which territory will be added is bound by the intergovernmental agreement negotiated pursuant to subsection (5) of this section to use the territory solely for park and open space purposes.
uilding, designed for use predominantly as a place of residency by a person, a family, or families.
(8.5) Subsections (3) and (8) of this section shall not apply to a minor boundary adjustment if the county to which territory will be added is bound by the intergovernmental agreement negotiated pursuant to subsection (5) of this section to use the territory solely for park and open space purposes.
(9) In addition to any other requirements contained in this section, prior to the initiation of any minor boundary adjustment in which territory is proposed to be stricken off of the counties of Adams, Arapahoe, or Jefferson and added to the city and county of Denver, a decision approving the proposed minor boundary adjustment shall be made by a majority vote of the six-member boundary control commission, established by section 1 of article XX of the state constitution.
(10) (Deleted by amendment, L. 2003, p. 1323, § 1, effective August 6, 2003.)
C.R.S. § 30-6-110 Boundaries - survey - action to settle
30-6-110. Boundaries - survey - action to settle. When the boundary lines of any county in this state are so indefinite that a portion of territory, by reason of such indefinite description, is claimed by two counties, and such fact appears by petition of the board of county commissioners of either county to the state engineer, it is the duty of such state engineer, in connection with the county surveyor of each of such counties, to run out and establish such lines as nearly as may be in accordance with such defective description, fix and define such boundary line by monuments in accordance with rules issued by the state board of licensure for architects, professional engineers, and professional land surveyors, and to furnish the board of county commissioners of each of said counties with a description of such line as soon thereafter as may be practical, deposit such survey as a land survey plat in each county, and file a Colorado land survey monument record on each monument found or set, as specified in section 38-53-104. When such line is established it shall be the boundary line between said counties, unless one of said counties, within six months from the day of filing the description of said line by the state engineer with the board of county commissioners of such county, commences an action in a court of competent jurisdiction in this state to determine and settle such disputed line, and prosecute the same with due diligence until its final determination, or has settled such disputed line, within said six months, by arbitration. If the county surveyor of either of such counties shall not appear or assist the state engineer in making such survey after due notice so to do, it shall in no manner affect or invalidate such survey, or the boundary lines as they may be fixed by such state engineer.
C.R.S. § 30-6-111 State engineer - reimbursement for expenses
30-6-111. State engineer - reimbursement for expenses. The office of the state engineer shall be reimbursed for the expenses of any survey conducted in connection with a boundary dispute pursuant to section 30-6-110, and such expenses shall be borne equally by the counties involved in the boundary dispute.
C.R.S. § 30-6-112 Boundaries - not changed
30-6-112. Boundaries - not changed. Nothing in this section and sections 30-6-110 and 30-6-111 shall be so construed as to authorize a change of any county line.
C.R.S. § 30-6-113 Compliance with boundary control commission requirements
30-6-113. Compliance with boundary control commission requirements. In addition to any other requirements, a decision approving the proposed annexation by a majority vote of the six-member boundary control commission established by section 1 of article XX of the state constitution shall be made prior to the initiation of any annexation procedures pursuant to this article to annex land from the counties of Adams, Arapahoe, or Jefferson to the city and county of Denver.
Source: Open US Law by Vaquill AI (CC BY 4.0)URL: https://leg.colorado.gov/sites/default/files/images/olls/crs2024-title-30.docxFetched: 10/6/2026