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 located 4.0 miles outside Springfield, Illinois, down Illinois East State Route 29. The village is exit 96A off Interstate 55.
Rochester is located at 39°45′2″N 89°32′30″W / 39.75056°N 89.54167°W / 39.75056; -89.54167 (39.750625, -89.541587). According to the 2010 census, Rochester has a total area of 2.431 square miles (6.30 km), of which 2.43 square miles (6.29 km) (or 99.96%) is land and 0.001 square miles (0.00 km) (or 0.04%) is water.
As of the census of 2000, there were 2,893 people, 1,075 households, and 868 families residing in the village. The population density was 1,372.9 people per square mile (529.4/km²). There were 1,099 housing units at an average density of 521.6 per square mile (201.1/km²). The racial makeup of the village was 98.65% White, 0.28% African American, 0.03% Native American, 0.38% Asian, 0.03% Pacific Islander, 0.10% from other races, and 0.52% from two or more races. Hispanic or Latino of any race were 0.69% of the population.
There were 1,075 households out of which 39.4% had children under the age of 18 living with them, 70.7% were married couples living together, 8.1% had a female householder with no husband present, and 19.2% were non-families. 18.1% of all households were made up of individuals and 9.9% had someone living alone who was 65 years of age or older. The average household size was 2.69 and the average family size was 3.05.
In the village, the population was spread out with 27.5% under the age of 18, 6.3% from 18 to 24, 25.2% from 25 to 44, 29.7% from 45 to 64, and 11.3% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 94.0 males. For every 100 females age 18 and over, there were 88.3 males.
The median income for a household in the village was $62,891, and the median income for a family was $73,191. Males had a median income of $50,875 versus $35,944 for females. The per capita income for the village was $26,881. About 0.8% of families and 1.2% of the population were below the poverty line, including 1.3% of those under age 18 and 0.9% of those age 65 or over.