Lewis Baker (born c. 1825, date of death unknown) was a patrolman in the New York Police Department who was simultaneously employed as a "slugger" for Tammany Hall. He was involved in voter intimidation and election fraud during the 1840s and 1850s. A close friend and associate of Irish mob boss John Morrissey, Baker frequently battled supporters of the nativist Know-Nothing movement for over a decade. He is most remembered however as the assassin of William "Bill the Butcher" Poole. Baker shot and killed Poole in a Broadway saloon during a brawl. Both Baker and Morrissey were placed on trial for murder, but were acquitted.