In a fight near Christiana, Pennsylvania, a group of escaped slaves and free Blacks led by William Parker fought off a federal posse seeking to arrest and return the escapees to slavery.

The Christiana Riot, also known as Christiana Resistance, or Christiana incident, was the successful armed resistance by free Blacks and escaped slaves to a raid led by a federal marshal to recover four escaped slaves owned by Edward Gorsuch of Maryland. The raid took place in the early morning of September 11, 1851, at the house in Christiana, Pennsylvania, of William Parker, himself an escaped slave. This took place after the federal Fugitive Slave Act of 1850 increased penalties for assisting escaped slaves and required state government officials, even in free states such as Pennsylvania, to assist in the recapture of slaves.

Christiana is a borough in Lancaster County, Pennsylvania, United States. The population was 1,100 at the time of the 2020 census.

William Parker was an American former slave who escaped from Maryland to Pennsylvania, where he became an abolitionist and anti-slavery activist in Christiana. He was a farmer and led a black self-defense organization. He was notable as a principal figure in the Christiana incident, 1851, also known as the Christiana Resistance. Edward Gorsuch, a Maryland slaveowner who owned four slaves who had fled over the state border to Parker's farm, was killed and other white men in the party to capture the fugitives were wounded. The events brought national attention to the challenges of enforcing the Fugitive Slave Law of 1850.