There are 20 stadiums in use by International League (IL) baseball teams. The oldest stadium is Sahlen Field, home of the Buffalo Bisons, which was built in 1988. The newest stadium is Polar Park, home of the Worcester Red Sox, which opened in 2021. Two stadiums were built in the 1980s, six in the 1990s, seven in the 2000s, four in the 2010s, and one in the 2020s. The highest seating capacity of all active stadiums is 16,600 at Buffalo's Sahlen Field. The stadium with the lowest capacity is CHS Field, the home of the St. Paul Saints, which seats 7,210. All stadiums use a grass surface.
Some 100 additional ballparks formerly hosted International League teams since the league's formation in 1884. These include stadiums from the Eastern League (1884), New York State League (1885), International Association (1888-1890), and Eastern Association (1891), each of which league officials consider part of its origins, and the Eastern League (1892–1911), which changed its name to the International League in 1912.[citation needed]