Duffy's Cut is the name given to a stretch of railroad tracks some 30 miles west of Philadelphia, USA, and originally built for the Philadelphia and Columbia Railroad in the summer and fall of 1832.

Railroad contractor Philip Duffy hired 57 Irish immigrants to lay this line through the area's densely wooded hills and ravines. The workers had recently arrived in Philadelphia from Donegal, Tyrone, and Derry, Ireland. Within two months, all 57 were dead.

All but the first three workers were buried in a shallow ditch along the railroad’s right of way without ceremony or funeral. No death certificates were ever filed.

Official record of the deaths at Duffy’s Cut stated the workers died of cholera, however, cholera usually causes 30-70% casualties in a population, while in this case 100% of the workers died leading to a theory that some may have been killed.

In August 2009, the Irish Times reported two skulls were uncovered that showed evidence of blunt-force trauma inflicted ante-mortem, suggesting the possibility of murder. More recently evidence of a mass murder, possibly fueled by local fear that the Irish would spread cholera, may be behind the Duffy's Cut mass grave..

A full investigation is expected to ensue as further excavation and testing is done on the remains.