Hiester Clymer was an American politician and white supremacist from the state of Pennsylvania. Clymer was a member of the Hiester family political dynasty and the Democratic Party. He was the nephew of William Muhlenberg Hiester and the cousin of Isaac Ellmaker Hiester. Although Clymer was born in Pennsylvania, he was adamantly opposed to Abraham Lincoln's administration and the Republican Party's prosecution of the American Civil War. Elected Pennsylvania state senator in 1860, Clymer opposed state legislation that supported the state Republican Party's war effort. After the American Civil War ended, Clymer unsuccessfully ran for the Pennsylvania Governor's office in 1866 on a white supremacist platform against Union Major-General John W. Geary. After his election to the U.S. House of Representatives in 1872 as a Democrat, Clymer would be primarily known for his investigation of Sec. William W. Belknap's War Department in 1876. Belknap escaped conviction in a Senate impeachment trial, and had resigned his cabinet position before being impeached by the House of Representatives. Having retired from the House in 1881, Clymer served as Vice President of the Union Trust Co. of Philadelphia and president of the Clymer Iron Co. until his death in 1884.

Isaac Ellmaker Hiester was a nineteenth century American political leader. A member of the Hiester Family political dynasty, he was also descended from the prominent Ellmaker family. The son of William Hiester, he was also a cousin of Hiester Clymer.