Robert McKnight (January 20, 1820 – October 25, 1885) was an American lawyer and politician who represented Pennsylvania's 22nd congressional district in the United States House of Representatives from 1859 to 1863.

Robert McKnight was born in Pittsburgh, Pennsylvania.

[2] MnKnight served as a member of the Pittsburgh City Council from 1847 to 1849, and was subsequently elected as a Republican to the Thirty-sixth and Thirty-seventh Congresses.

After his final term in 1863, he resumed the practice of law.

[3] Early Pittsburgh Pirates owner Denny McKnight was his son.