The city lies on a mostly flat plain which encompasses much of the surrounding countryside. There is more hilly terrain near the Sangamon River. Lake Springfield, a large artificial lake owned by City Water, Light & Power company called CWLP, supplies the city with recreation and drinking water. Weather is fairly typical for middle latitude locations, with hot summers and cold winters. Spring and summer weather is like that of most midwestern cities; severe thunderstorms are common. Tornadoes hit Springfield in 1957 and 2006.
The city is governed by a mayor-council form of government. The city proper is also the "Capital Township" governmental entity. In addition, the government of the state of Illinois is also based in Springfield. State government entities located in the city include the Illinois General Assembly, the Illinois Supreme Court and the Office of the Governor of Illinois. There are three public and two private high schools in Springfield. Public schools in Springfield are operated by District No. 186. The economy of Springfield is marked by government jobs, which account for a large percentage of the work force in the city.