Thomas Buchanan (November 19 1808 – September 3 1841) was the second governor of Liberia and a cousin of James Buchanan President of the United States. He came to Liberia as the envoy of the American Colonization Society in the 1830s. He worked first as an administrator in Grand Bassa which later had its capital named Buchanan in his honor. In 1839 Buchanan was sent to Monrovia where he became the second governor of Liberia after the death of Jehudi Ashmun.
