Rochester is a village in Sangamon County, Illinois, United States. The population was 2,893 at the 2000 census, and 3,246 at a 2009 estimate. The village was settled in 1819, and is located in Rochester Township.
Rochester is part of the Springfield, Illinois Metropolitan Statistical Area.
Rochester is located 4.0 miles outside Springfield, Illinois, down Illinois East State Route 29. The village is exit 96A off Interstate 55.