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. He attended the common schools and a private school at Xenia, Ohio. He graduated from Princeton College in 1839.^[1]

McKnight studied law, was admitted to the bar in 1842, and joined a law partnership with Henry S. Magraw in Pittsburgh. In 1846, he was hired to be a solicitor for the Bank of Pittsburgh.^[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. He served his district during the American Civil War.

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

McKnight died in Pittsburgh in 1885. He was interred at the Allegheny Cemetery.^[3] Early Pittsburgh Pirates owner Denny McKnight was his son.

• Robert McKnight, in later years