Martinez Flag

Martinez

County Seat:
Yes
Area (mi²):
12.643
State:
California

Martinez is a city located in Contra Costa County, California. Martinez has a 2026 population of 37,006. It is also the county seat of Contra Costa County. Martinez is currently growing at a rate of 0.8% annually but its population has decreased by -0.49% since the most recent census, which recorded a population of 37,187 in 2020.

37K
Total Population
2,927
Density (mi²)
294 0.8%
Growth

Nearby Cities

Sources

  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)