From 1865 to 1867 the district included Bureau, LaSalle, Livingston and Woodford counties. From 1901 until 1947 the 11th congressional district included Kane, DuPage, McHenry and Will Counties. Following the Congressional Apportionment Act of 1947, the district covered a portion of Cook County and the far northwest side of Chicago roughly centered around Norwood Park. The district was not changed by 1951's redistricting. In 1961, the district was widened westward to the Des Plaines River and east into parts of Lincoln Square. The district covered the northwest side of Chicago until the early 1990s when it moved closer to its current area, encompassing most of LaSalle and Grundy Counties, the southern part of Will County, the northern part of Kankakee County and a small portion of southeastern Cook County. The Illinois Congressional Reapportionment Act of 2001 (10 ILCS 76) defined its boundaries following the U.S. Census 2000.