Isaac Ellmaker Hiester (1824-1871) was an American political leader of the 19th Century. He was a member of the Hiester Family political dynasty. He was the son of William Hiester and cousin of Hiester Clymer.
Hiester was born in New Holland, Pennsylvania in Lancaster County, Pennsylvania on May 29, 1824. He attended Yale College (now Yale University), studied law, and was admitted to the bar in 1845. He began a successful law practice in Lancaster, Pennsylvania.
In 1848, he was elected Deputy District Attorney for Lancaster County and held the post until 1851. In 1852, he successfully ran for a seat in the United States House of Representatives as Whig. He was defeated for reelection in 1854 because his opinions on slavery were at odds with his constituency. He again ran unsuccessfully in 1856. Hec retuned to his law practice and in 1868 served as a delegate to the Democratic National Convention.
He died in Lancaster, Pennsylvania on February 6, 1871.