Bernalillo is a town in Sandoval County, New Mexico, in the United States. As of the 2000 census, the town population was 6,611. It is the county seat of Sandoval County. Bernalillo is part of the Albuquerque Metropolitan Statistical Area. According to the United States Census Bureau, the town has a total area of 4.7 square miles (12 Square Kilometer), of which, 4.6 square miles (12 Square Kilometer) of it is land and 0.1 square miles (0.26 Square Kilometer) of it (2.34%) is water.