|Lake County, Illinois|
Location in the U.S. state of Illinois
Illinois's location in the U.S.
|Founded||March 1, 1839|
|Named for||Lake Michigan|
|• Total||1,368 sq mi (3,543 km2)|
|• Land||444 sq mi (1,150 km2)|
|• Water||925 sq mi (2,396 km2), 67.6%|
|• Density||1,586/sq mi (612/km2)|
|Congressional districts||6th, 10th, 14th|
|Time zone||Central: UTC−6/−5|
Lake County is a county in the northeastern corner of the U.S. state of Illinois. According to the 2010 census, it has a population of 703,462, making it the third-most populous county in Illinois. Its county seat is Waukegan. Originally part of McHenry County, the townships composing Lake County were carved out into a separate county in 1839.
Lake County is one of the collar counties of the Chicago-Naperville-Elgin, IL-IN-WI Metropolitan Statistical Area. It is located along the shore of Lake Michigan.
According to the 2000 census, Lake County is the 31st richest county by per capita income. The lakefront communities of Lake Forest, Lake Bluff, and Highland Park are part of the affluent North Shore area.