William Marvin (April 14, 1808 – July 9, 1902) was an American lawyer, politician, and judge. He was the seventh Governor of Florida
Marvin was born in Fairfield, New York. He 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 Territorial Council of 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 the newly-created United States District Court for the Southern District of Florida, to the seat created by 9 Stat. 131. Confirmed by the Senate on March 3, 1847. He received 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.
Marvin was appointed provisional governor of Florida on July 13, 1865, by President Andrew Johnson, to reestablish the government of the state after the end of the American Civil War. Marvin left office on December 20, 1865. The Florida Legislature elected him to the United States Senate as a Democrat, but the U.S. Senate refused to recognize the election and denied him a seat. Following the decision by the federal government to reconstruct the former Confederacy, he refused to run for any office.
In 1867, he left Florida and moved to Skaneateles, New York. He remained in private practice until his death in Skaneateles in 1902.
Marvin was the author of a nationally-recognized textbook entitled Law of Wreck and Salvage, on salvage law.