Lake St. Clair, Missouri Demographics & Population 2026

A note before these figures: with a population of 872, Lake St. Clair'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

Lake St. Clair is a small community located in Missouri, within Franklin County. The total population is 872. It ranks as the 398th most populous out of 1,062 Census-designated places in Missouri.

Age Demographics

The median age in Lake St. Clair is 28.5 years. This is 27% lower than the state median of 39.0 years. With 35.7% of the population under 18, Lake St. Clair has a notably young demographic profile, suggesting a family-oriented community.

Economy, Income & Housing

The median household income in Lake St. Clair is $81,397. This is 15% higher than the state median of $70,702. It is also about the same as the national median of $80,734. The ACS records no residents below the poverty line in Lake St. Clair. 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 11.0%. This is 174% higher than the state rate of 4.0%. The median home value is $227,800. Housing costs are 1% lower than the state median of $230,300. With a home-value-to-income ratio of just 2.8x, Lake St. Clair is one of the most affordable housing markets in the area. 94.5% of occupied housing units are owner-occupied. This homeownership rate is 39% higher than the state average of 68.1%.

Race & Ethnicity

Lake St. Clair has a predominantly White (non-Hispanic) population, comprising 93.0% of all residents. Hispanic or Latino residents account for 2.4%. The Hispanic or Latino population (2.4%) is well below the state average of 5.2%.

Education

28.1% of residents aged 25 and older hold a bachelor's degree or higher. This is 13% lower than the state rate of 32.4%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 88.4%.

Data Sources & Methodology

All demographic data for Lake St. Clair, Missouri 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 Missouri state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 1,062 Census-designated places in Missouri. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.