Thomas Taggart (November 17, 1856March 6, 1929) was the political boss of the Democratic Party in Indiana for the first quarter of the twentieth century and remained an influential political figure in local, state, and national politics until his death. Taggart was elected auditor of Marion County, Indiana (1886–1894), and mayor of Indianapolis (1895 to 1901). His mayoral administration supported public improvements, most notably the formation of the city's park and boulevard system. He also served as a member of the Democratic National Committee (1900–1916) and as its chairman (1904–1908). Taggart was appointed to the U.S. Senate in March 1916, but lost the seat in the November election.