Thomas Armstrong Morris (December 26, 1811 – March 23, 1904) was an American railroad executive and civil engineer from Kentucky and a soldier, serving as a brigadier general of the Indiana Militia in service to the Union during the early months of the American Civil War. During the Western Virginia Campaign in 1861, he played an important role in leading regiments from West Virginia, Indiana, and Ohio in clearing the Confederate army from western Virginia during the Battle of Philippi, a move that helped bolster pro-Union sentiment and contributed to the creation of the separate state of West Virginia. Morris was also instrumental in the planning and construction of the postbellum Indiana State House.