William Marvin (April 14, 1808 – July 9, 1902) was an American lawyer, politician, and United States federal judge. He was the seventh Governor of Florida
Born in Fairfield, New York, Marvin read law in 1834 and entered private practice in Phelps, New York in 1834. President Andrew Jackson appointed him United States Attorney for the Southern District of Florida Territory at Key West in 1835, and he served in that position until 1839. Marvin served as a member of the Florida Territorial Council, governing the Florida Territory, in 1837.
Marvin served as a U.S. territorial judge on the U.S. District Court for the Southern District of Florida Territory from 1839 to 1847. Florida became a U.S. state in 1845. On March 2, 1847, President James K. Polk nominated him to a seat on the newly created United States District Court for the Southern District of Florida, created by 9 Stat. 131. Confirmed by the Senate on March 3, 1847, he received his commission on March 3, 1847.
Marvin resigned from the court on July 1, 1863 (since 1861, during the American Civil War, Florida had seceded from the Union and been part of the Confederacy). Marvin was in private practice in New York City in 1863 to 1865.