According to a Business Journal analysis of the U.S. Census Bureau’s city-level Vintage Population Estimates, the municipalities that saw the largest year-over-year increases in 2025 generally shared two key traits: relative affordability and an influx of new homes. Using 2020 to 2025 numbers, the fastest-growing towns and cities with populations over 5,000 in Southeastern Pennsylvania include:

• Kennett Square, 2025 population: 6,893, up 16% since 2020
• Bridgeport, population: 5,758, up 15% 
• Phoenixville, population: 20,356, up 10% 
• West Chester, population: 19,591, up 5% 
• Downingtown, population: 8,384, up 5% 
• Collegeville, population: 5,287, up 5% 
• Chester, population: 33,996, up 4% 

Source: Philadelphia Business Journal; 5/27/2026