Cibola County is a county in the U.S. state of New Mexico. As of the 2010 census, the population was 27,213. Its county seat is Grants. It is New Mexico's youngest county, and the third youngest county in the United States, created on June 19, 1981, from the westernmost four-fifths of the formerly much larger Valencia County. Cibola County comprises the Grants, New Mexico Micropolitan Statistical Area. The county is a rich mining area with numerous Uranium mines.