The Plug Uglies were an American Nativist criminal street gang, sometimes referred to loosely as a political club, that operated in the west side of Baltimore, Maryland, from 1854 to 1865.

Like similar associations in Baltimore and other U.S. cities during this period, the Plug Uglies' street influence made them useful to party politicians anxious to control the polls on election days.

Accounts of the Washington riot appeared in newspapers nationally and gained widespread notoriety for the Plug Uglies.

Gambrill's trial (presided over by judge Henry Stump) and the subsequent deadly violence relating to it, made the crime one of the most sensational of the era.

It was largely responsible for the creation of modern policing and a paid, professional fire department, as well as court and electoral reforms.