N.M. Stat. § 3-2-3

A. Urbanized territory is that territory within the same county and within five miles of the boundary of any municipality having a population of five thousand or more persons and that territory within the same county and within three miles of a municipality having a population of less than five thousand persons, except that territory in a county declared by an ordinance of the board of county commissioners to be a traditional historic community shall not be considered urbanized territory and shall not be annexed by a municipality unless it is considered for annexation pursuant to a petition requesting annexation signed by a majority of the qualified electors within the traditional historic community.

B. No territory within an urbanized territory shall be incorporated as a municipality unless the:

(1) municipality or municipalities causing the urbanized territory approve, by resolution, the incorporation of the territory as a municipality;

(2) residents of the territory proposed to be incorporated have filed with the municipality a valid petition to annex the territory proposed to be incorporated and the municipality fails, within one hundred twenty days after the filing of the annexation petition, to annex the territory proposed to be incorporated; or

(3) residents of the territory proposed to be annexed conclusively prove that the municipality is unable to provide municipal services within the territory proposed to be incorporated within the same period of time that the proposed municipality could provide municipal service.

C. A traditional historic community may become incorporated even though it is located within what is defined as urbanized territory pursuant to Subsection A of this section, by following the procedures set forth in Sections 3-2-5 through 3-2-9 NMSA 1978 .