Lake Nacimiento is a census-designated place (CDP) in northern San Luis Obispo County, California, United States.

[2] According to the United States Census Bureau, the CDP has a total area of 10.3 square miles (27 km2), 99.77% of it land and 0.23% of it water.

[3] The 2010 United States Census[6] reported that Lake Nacimiento had a population of 2,411.

The racial makeup of Lake Nacimiento was 2,153 (89.3%) White, 12 (0.5%) African American, 44 (1.8%) Native American, 24 (1.0%) Asian, 5 (0.2%) Pacific Islander, 75 (3.1%) from other races, and 98 (4.1%) from two or more races.

237 households (23.6%) were made up of individuals, and 69 (6.9%) had someone living alone who was 65 years of age or older.

As of the census[7] of 2000, there were 2,176 people, 904 households, and 676 families residing in the CDP.

19.1% of all households were made up of individuals, and 6.1% had someone living alone who was 65 years of age or older.

In the California State Legislature, Lake Nacimiento is in the 17th Senate District, represented by Democrat John Laird, and in the 35th Assembly District, represented by Democrat Jasmeet Bains.