Charles Gradison Keenan (1813–1870) was a politician and physician in early statehood Texas who served as Speaker of the Texas House of Representatives during the Third Texas Legislature. Keenan was born 28 February 1813 in Giles County, Tennessee, to Leanna (McCormick) and John Keenan. John Keenan was the first treasurer of Walker County, Texas while Charles Keenan was the first physician in Huntsville, Texas. Charles Keenan was a United States Army surgeon in the Indian campaigns before arriving in Texas. Keenan died 15 June 1870 in Huntsville.