The 1st Congressional District of Illinois includes part of Cook County, and has been represented by Democrat Bobby Rush since January 1993. This district includes much of the South Side of Chicago, extending into the city's southwest suburbs until reaching the border of Will County, and covers 97.84 square miles (253.41 km²), making it one of the 40 smallest districts in the U.S. although there are four smaller districts in Illinois. It is adjacent to the 2nd District to the east and south, the 7th District to the north, and the 3rd and 13th Districts to the west, and also borders the 11th District at its southwest corner; the district's northeast border follows Lake Michigan's shoreline for almost a mile. It is the home district of U.S. President-elect Barack Obama. The district was created following the 1830 Census and came into being in 1833, five months before Chicago was organized as a town; the state was previously represented in Congress on an at large basis. The 1st District initially included southwestern Illinois until 1853 and the state's northern edge until 1863; since that time the district has included all or part of Cook County, with its population primarily residing on Chicago's South Side since 1883.
The district has the highest percentage (65.5) of African American residents in the nation, and has been represented in Congress by African Americans since 1929. It is also one of the most reliably Democratic districts in the country, although not quite to the extent that it was during the 1980s when over 90% of the district's residents were black. The district has not elected a Republican to Congress since 1932, and Democratic candidates routinely receive over 80% of the vote here.