Patty Cannon, whose birth name may have been Lucretia Patricia Hanly (c. 1759/1760 or 1769 – May 11, 1829), was an illegal slave trader, serial killer, and the co-leader of the multi-racial Cannon–Johnson Gang of Maryland–Delaware.

The only time any real efforts to arrest and convict the gang is when authorities found the bodies of several white slave traders, a child and a baby.

[2] In 1829, Cannon was the only member of the gang captured and indicted in Delaware for four murders after the remains of four black people (including three children) were discovered on property she owned.

[6][page needed] Some time after this, Cannon's daughter married Joe Johnson, who became the mother's most notorious partner in crime.

[7] The Cannon–Johnson gang included whites and blacks, among them Henry Carr and John Purnell, described as a "yellow" man or mulatto, who used several aliases.

[11] In addition, nearby Philadelphia, Pennsylvania had the largest population of free black Americans in the North and no professional police force in the antebellum years.

[7] Cannon's kidnapping forays could troll waterfront areas throughout the region, enticing young men aboard their boat to help decoy workers.

[9] But Philadelphia had an active mayor, Joseph Watson, a Quaker, who made concerted efforts on behalf of stolen free blacks with officials in Mississippi and Alabama, which included paying for gathering of affidavits and, in the case of Cornelius Sinclair in 1827, a white witness to travel to Alabama to attest to his identity.

They were often put aboard a schooner traveling down the Nanticoke River to the Chesapeake Bay, from where they were shipped to Georgia and other slave markets.

Local law enforcement officials were reluctant to halt the illegal operations, and may have been afraid of the gang's reputation for violence.

[12] According to depositions from victims who gained freedom and returned to homes in the North, Joe Johnson kept the captives in leg irons.

Lydia Smith, a 25-year-old free black woman, testified that she was kidnapped in 1825 and kept in Cannon's home before being moved to Johnson's tavern.

[9] In the mid-1820s, Mayor Joseph Watson of Philadelphia and Governor John Andrew Schulze cooperated to retrieve kidnapped young blacks from Mississippi and to prosecute the Cannon–Johnson gang.

In 1826 Watson offered a $500 (~$13,465 in 2023) reward for information leading to the arrest of members, and Schulze issued orders of extradition to the states of Virginia, Alabama and Mississippi.

[2][16] In 1829, bodies of four black people, including three children, were discovered buried on farm property which Cannon owned in Delaware.

He had grown up in her household and participated in her crimes, sometimes serving as a decoy to make free blacks feel safe in working with him on a task.

Before that land was developed as a parking lot in the 20th century, her remains, along with those of two other women, were exhumed and reburied in a potter's field near the new jail.

[18] In the 1990s, a historical marker was placed on the highway near what is sometimes called the "Patty Cannon House" in Reliance, Maryland, but this structure was built about 1840.

A housing development, established in the early 1970s, stands on the Delaware side of the Nanticoke River and is named the Patty Cannon Estates.