Springfield is the capital city of the U.S. state of Illinois and the county seat of Sangamon County. The city's population was 114,394 at the 2020 census, which makes it the state's seventh most-populous city, the second largest outside of the Chicago metropolitan area (after Rockford), and the largest in central Illinois. Approximately 208,000 residents live in the Springfield metropolitan area.

Springfield was settled by European-Americans in the late 1810s, around the time Illinois became a state. The most famous historic resident was Abraham Lincoln, who lived in Springfield from 1837 until 1861, when he went to the White House as President of the United States. Major tourist attractions include multiple sites connected with Lincoln including the Abraham Lincoln Presidential Library and Museum, Lincoln Home, Old State Capitol, Lincoln-Herndon Law Offices, and the Lincoln Tomb. Largely on the efforts of Lincoln and other area lawmakers, as well as its central location, Springfield was made the state capital in 1839.

Springfield lies in a valley and plain near the Sangamon River. Lake Springfield, a large reservoir owned by the municipal City Water, Light & Power company (CWLP), provides city residents with recreation and drinking water. Weather is fairly typical for middle latitude locations, with four distinct seasons.

The city has a mayor–council form of government and governs the Capital Township. The government of the state of Illinois is based in Springfield. State government institutions include the Illinois General Assembly, the Illinois Supreme Court and the Office of the Governor of Illinois. There are three public and three private high schools in Springfield. Public schools in Springfield are operated by District No. 186. Springfield's economy is dominated by government jobs, plus the related firms that deal with the state and county governments and justice system, and health care and medicine.