Springfield is the capital of the State of Illinois and the county seat of Sangamon County. The city was founded in 1819, became the county seat in 1823, and received its city charter in 1840. It was made the capital of Illinois in 1837, and the Legislature convened here for the first time in 1839. As of 2005, the city population was around 135,000, disregarding unincorporated and surburban areas.

The city is the site of a number of attractions centered around President Abraham Lincoln, who started his political career in Springfield. These include a national park site, the Lincoln Home Historic Site, as well as the preserved surrounding neighborhood; the Lincoln-Herndon Law Offices State Historic Site; the Old State Capitol State Historic Site; the newly built Abraham Lincoln Presidential Library and Museum; the train depot from where he departed to Washington; and his burial mausoleum. The Museum of Funeral Customs, located near Lincoln's tomb, also features exhibits related to the president's funeral. North of Springfield, near the village of Petersburg, is New Salem (Menard County), Illinois, a restored hamlet of log cabins recreating New Salem, where Lincoln lived as a young man. With the opening of the Presidential Library and Museum in 2004, the city has seen a number of prominent visitors, including Former Supreme Court Justice Sandra Day O'Connor and the Emir of Qatar.