Thomas Holliday Hicks (September 2, 1798 – February 14, 1865) was a politician in the divided border-state of Maryland during the American Civil War. As governor, opposing the Democrats, his views accurately reflected the conflicting local loyalties. He was pro-slavery but anti-secession. Under pressure to call the General Assembly into special session, he held it in the pro-Union town of Frederick, where he was able to keep the state from seceding. In December 1862, Hicks was appointed to the U.S. Senate, where he endorsed Abraham Lincoln's re-election in 1864, but died soon afterwards.