Explore San Marcos local geography, civic resources and voter guides, with dated official population and registration facts for San Diego County.
At a glance: San Marcos is an incorporated city in San Diego County. Population: 97,554 (California Department of Finance estimate as of January 1, 2026). Registered voters: 56,373 (California Secretary of State, as of September 4, 2026).
San Marcos is an inland city in northern San Diego County set among hills and valleys. It is a charter city with council-manager government: the City Manager’s page describes the appointed manager administering city programs under council policy direction. The City Clerk serves as the municipal election official responsible for nomination papers, city ballot measures and conducting municipal elections, and also provides public-records access to documents such as building plans, contracts and reports. That combination makes the Clerk’s page the practical starting point for both candidacy questions and records requests. Among the city’s park facilities, Double Peak Park stands out in the city’s facility directory for its telescope, trail connection, picnic facilities, play equipment and amphitheater — a hilltop park rather than a flat neighborhood green. For registration and vote-by-mail, use the San Diego County Registrar of Voters.
Double Peak Park, which the city’s facility page also describes as having a trail connection, picnic facilities and an amphitheater.
The City Clerk serves as the municipal election official, handling nomination papers, city ballot measures and the conduct of elections.
The City Clerk’s public-records service provides the route to request those records.
56,373 (California Secretary of State, as of September 4, 2026).
CA Slates began with shared voter guides in 2012 and expanded into its current publication family and connected program.