Peter Humphries Clark (March 29, 1829 – June 21, 1925) was an American abolitionist and speaker.

This was largely due to the efforts of Peter's uncle, John Isom Gaines.

He participated in the Ohio Conventions of Colored Men, and edited and published his own weekly newspaper.

He then became editor of a Free Soil Party journal published in Newport, Kentucky, owned by William S. Bailey.

[3] He became principal of Gaines High School in 1866 and held that post until 1886, when he was fired on political grounds.

Clark was able to obtain a writ of habeas corpus from Judge John McLean so the case could go before the court.

The speech was decried by the local press, but was warmly received by socialists, and Clark ran as a Workingmen's Party candidate for state school commissioner the same year, becoming the first black socialist to run for office in the United States: he was not elected, but won about 8,000 votes.

[10] In 1882, he aided county Democrats in organizing a civil rights bill, which passed into law.