Norristown is a municipality and the county seat of Montgomery County, Pennsylvania in the Philadelphia metropolitan area. Located along the Schuylkill River approximately 6 miles from the Philadelphia city limits, Norristown has a population of 34,324 as of the 2010 U.S. Census. It is the fourth most populous municipality in the county and second most populous borough in Pennsylvania. It is the largest non-township municipality in Montgomery County.