WY Stat § 15-1-421 (2021)
2021 Wyoming Statutes|Title 15 - Cities and Towns|Chapter 1 - General Provisions|Article 4 - Annexation; Determination of Boundaries; Addition and Exclusion of Land|Section 15-1-421 - Municipal De-Annexation.

15-1-421. Municipal de-annexation.| (a) Any landowner within a city or town may petition the governing body of the city or town to have his land or a portion of it de-annexed and the boundaries of the city or town redrawn so their land is outside the city or town boundaries. The landowner shall file the petition with the clerk of the affected city or town and shall also provide a copy of the petition to the county commissioners of the affected county. The county commissioners shall, within sixty (60) days, prepare a report on the impact of the de-annexation. The affected city or town may not take any action on the petition for de-annexation until after the sixty (60) day period. The commissioners may establish rules and regulations for the area to be de-annexed which are consistent with county land use plans and zoning ordinances.  (b) The petitioner shall be responsible for publishing a public notice of the petition in a newspaper of general circulation in the affected municipality no more than ten (10) days after filing the petition with the municipal clerk. The notice shall also include a map showing identifiable landmarks and boundaries.  (c) The governing body of the city or town may by ordinance provide for this de-annexation and redrawing of boundaries provided that:  (i) The owners of all the land to be de-annexed either sign the petition for de-annexation or consent to the de-annexation within one hundred twenty (120) days after the final passage of the de-annexation ordinance and before its effective date. The passage of the ordinance shall serve as the consent of the city or town for any land owned by the city or town within the area to be de-annexed;  (ii) The ordinance is adopted within one hundred twenty (120) days after the receipt of the de-annexation petition and within one hundred eighty (180) days after the landowner's signature of the petition, unless a further consent of all the landowners is obtained before the effective date of the ordinance; and  (iii) If the de-annexation causes land within the city or town boundaries to no longer be contiguous with the rest of the city or town, the de-annexation ordinance may be adopted only with the consent of all the owners of the land to be isolated by the de-annexation.  (d) If the city or town owns any rights-of-way, easements, streets or other property or improvements within the area to be de-annexed it may:  (i) Vacate or abandon them;  (ii) Transfer them to the county government with the consent of the county commissioners;  (iii) Agree to transfer them to another city or town upon completion of the annexation of all or part of the de-annexed land to that other city or town;  (iv) Retain ownership of them.  (e) No de-annexation shall create an area which is situated entirely within the municipality but is not a part of the municipality.  (f) The landowner petitioning to have land de-annexed and his successors and assigns shall remain liable for any assessments incurred or levied while the land was within the city or town boundaries and for all mill levies necessary to repay any indebtedness that was outstanding at any time the property was within the city or town boundaries. Neither the de-annexation nor subsequent annexation to or incorporation as another city shall increase or decrease these liabilities.