St. Clair is a city located in Pennsylvania. With a 2020 population of 2,816, it is the 330th largest city in Pennsylvania and the 6439th largest city in the United States . St. Clair is currently declining at a rate of -0.25% annually and its population has decreased by -6.26% since the most recent census, which recorded a population of 3,004 in 2010. St. Clair reached it's highest population of in . Spanning over 1 miles, St. Clair has a population density of 2,284 people per square mile.
The average household income in St. Clair is $54,379 with a poverty rate of 17.40%. The median rental costs in recent years comes to $717 per month, and the median house value is $69,000. The median age in St. Clair is 46.3 years, 47.4 years for males, and 40.4 years for females.