Peterloo massacre, public disturbance in St. Peter's Field, Manchester, England, Aug. 16, 1819, also called the Manchester massacre. A crowd of some 60,000 men, women, and children were peaceably gathered under the leadership of Henry Hunt to petition Parliament for the repeal of the corn laws and for parliamentary reform. The magistrates ordered the meeting to disband. A cavalry charge to aid the untrained Manchester yeomanry resulted in 11 deaths and injuries estimated at over 400. The government's endorsement of the magistrates' action created widespread indignation, which added moral force to the reform movement. The name Peterloo, later given the incident, was suggested by the name Waterloo.
See F. A. Bruton, Three Accounts of Peterloo (1921); studies by G. R. Kestevan (1967) and J. Marlow (1969).