Port Costa, California Demographics & Population 2026

A note before these figures: with a population of 296, Port Costa's ACS estimates come from a small number of survey responses and carry wide margins of error. Individual percentages below — particularly rates that round to 0% or 100% — are approximations, not precise measurements. See data.census.gov for the published margins of error.

Population Overview

Port Costa is a small community located in California, within Contra Costa County. The total population is 296. It ranks as the 1318th most populous out of 1,570 Census-designated places in California.

Age Demographics

The median age in Port Costa is 67.3 years. This is 78% higher than the state median of 37.9 years. Only 12.8% of residents are under 18, indicating fewer families with children. 36.8% of residents are 75 or older, suggesting a significant retirement-age population with implications for healthcare services and senior housing.

Economy, Income & Housing

The median household income in Port Costa is $38,929. This is 61% lower than the state median of $99,122. It is also 52% lower than the national median of $80,734. The ACS records no residents below the poverty line in Port Costa. In a community this small the estimate rests on very few survey responses, so it should be read as an absence of measurement rather than a measured absence of poverty. The unemployment rate is 9.0%. This is 36% higher than the state rate of 6.6%. The median home value is $600,000. Housing costs are 18% lower than the state median of $734,700. The home-value-to-income ratio of 15.4x suggests that housing affordability is a significant concern for many residents. 56.2% of occupied housing units are owner-occupied.

Race & Ethnicity

Port Costa has a predominantly White (non-Hispanic) population, comprising 90.2% of all residents. Hispanic or Latino residents account for 9.8%. The White (non-Hispanic) population is significantly higher than the state average (90.2% vs 33.8%). The Hispanic or Latino population (9.8%) is well below the state average of 40.2%.

Education

27.9% of residents aged 25 and older hold a bachelor's degree or higher. This is 25% lower than the state rate of 37.1%. Nationally, 35.7% of adults hold at least a bachelor's degree. No surveyed resident aged 25 or older reported leaving school before earning a high school diploma, though a rate of exactly 100% reflects the limits of a small sample.

Data Sources & Methodology

All demographic data for Port Costa, California is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against California state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 1,570 Census-designated places in California. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.