Oscar Stanton De Priest was an American politician and civil rights advocate from Chicago. A member of the Illinois Republican Party, he served as a U.S. Representative from Illinois's 1st congressional district from 1929 to 1935. He was the first African American to be elected to Congress in the 20th century. During his three terms, he was the only African American serving in Congress. He was also the first African-American U.S. Representative from outside the southern states.

Illinois's first congressional district is a congressional district in the U.S. state of Illinois. Based in Cook County, the district includes much of the South Side of Chicago and continues southwest to Joliet.