N.M. Stat. § 4-27-1
All that part of the territory of New Mexico comprised within the following boundaries and limits, to wit: commencing at the Mule springs, in Mule pass, in Cook's canyon range, in the county of Grant, and running thence in a northwesterly direction along the summit of the Mimbres mountains to the north boundary line of Grant county; thence west on said north boundary line to the one hundred and eighth degree of longitude west of Greenwich; thence north on said degree of longitude to the point where the same intersects the north line of township line ten south, of New Mexico, being along the north line of [sic] township ten south, range eleven west of the [principal] meridian of New Mexico; thence east on said township line to the principal meridian of New Mexico; thence south on said principal meridian to the south line of township seventeen south, of the United States survey; thence west along said south line of said township number seventeen south, to the southwest corner of range four west, New Mexico principal meridian; thence south on the west line of said range line number four west of said principal meridian of New Mexico, to the southwest corner of township number nineteen south, of range four west, New Mexico; thence west along the south line of township number nineteen south, to the southwest corner of township nineteen south, range seven west, New Mexico principal meridian; thence west-northwest to the place of beginning on said south line to the boundary line of Grant county, shall form and constitute a new county, to be known as and called Sierra county: provided, that the property thus separated from the county of Socorro shall not be exempt from its share of taxation to pay the outstanding bonded indebtedness of Socorro county.
NMS § 4-27-1