St. Clair is a city located in Pennsylvania. With a 2020 population of 2,795, it is the 333rd largest city in Pennsylvania and the 6454th largest city in the United States. St. Clair is currently declining at a rate of -0.82% annually and its population has decreased by -6.96% since the most recent census, which recorded a population of 3,004 in 2010. St. Clair reached it's highest population of 13,080 in 1920. Spanning over 1 miles, St. Clair has a population density of 2,267 people per square mile.
The average household income in St. Clair is $49,698 with a poverty rate of 14.98%. The median rental costs in recent years comes to $665 per month, and the median house value is $67,600. The median age in St. Clair is 46.2 years, 46.8 years for males, and 43.8 years for females. For every 100 females there are 85.0 males.