Tom Dennison, known as Pickhandle or Old Grey Wolf, (October 26, 1858 – February 14, 1934) was an American political boss and racketeer in Omaha, Nebraska. A politically savvy, culturally astute gambler, Dennison was in charge of the city's wide crime rings, including prostitution, gambling and bootlegging in the 1920s. Dennison is credited with electing "Cowboy" James Dahlman mayor of Omaha eight times, and when losing an election, inciting the Omaha Race Riot of 1919 in retribution against the candidate who won.