Joseph Pomeroy Root (April 3, 1826 – July 20, 1885) was an American doctor, politician, and leader of the Kansas Free Staters. A descendant of an old New England family, Root was the great-grandson of Revolutionary War General Seth Pomeroy. He graduated from the Berkshire Medical College in Pittsfield and practiced medicine in New Hartford, Connecticut for five years. In 1855 he was elected to the Connecticut House of Representatives, as a Whig.