There are 12 US Post Offices in Sandoval County serving a total of 127,014 residents equating to 10,585 residents per post office. It's estimated that approximately 202,729 packages are handled across the 12 county post offices annually. Sandoval County is a county located in the U.S. state of New Mexico. As of the 2010 census, the population was 131,561, making it the fourth-most populous county in New Mexico. The county seat is Bernalillo. Sandoval County is part of the Albuquerque, NM Metropolitan Statistical Area."