William Jefferson Hardin (c. 1831 – September 13, 1889) was an American politician who was the first African American member of the Wyoming Legislature. Hardin was born in Russellville, Kentucky, and grew up in Kentucky while being raised by Shakers. He participated in the California Gold Rush and briefly in a Union Army unit during the American Civil War before moving to the western United States. He lived in Colorado and worked at the United States Mint l. He was a delegate to the 1872 Republican National Convention. He moved to Wyoming after bigamy allegations resulted in him being fired. In Wyoming, he was elected to the Territorial House of Representative. After leaving Wyoming he lived in Utah until his suicide in 1889.