Joseph Mosley Root (October 7, 1807 – April 7, 1879) was a U.S. Representative from Ohio.

The son of Joseph Root III & Tryphena Mosley he was born October 7, 1807, in Brutus, New York. Root pursued classical studies and later studied law in Auburn, New York. He moved to Ohio in 1829, where he was admitted to the bar in 1830 and commenced practice in Norwalk.

In 1832-1833, Root was Mayor of Sandusky, Ohio.^[1] In 1835, Root married Mary S. Buckingham in Norwalk. They had five daughters.^[1] Root was elected prosecuting attorney of Huron County in 1837. He served as a member of the State Senate in 1840 and 1841.

Root was elected as a Whig to the Twenty-ninth Congress. He was reelected to the Thirtieth Congress and reelected as a Free-Soil candidate to the Thirty-first Congress (March 4, 1845 – March 3, 1851). In 1848, he introduced a resolution that recommended New Mexico and California have territorial governments which excluded slavery.^[2] He served as chairman of the Committee on Expenditures in the Department of the Treasury (Thirtieth Congress). He served as Presidential elector on the Republican ticket in 1860. He was appointed United States Attorney for the northern district of Ohio in 1861. He was again a member of the Ohio Senate in 1869. He served as Democratic delegate to the State constitutional convention in 1873. He was an unsuccessful Democratic candidate for probate judge of Erie County in 1875.