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On 14 August 2003, three 345-kV transmission circuits in northeastern Ohio contacted overgrown trees during a 40-min time span, starting a chain of events that culminated in the collapse of the electrical grid across the eastern Great Lakes region, the northeastern United States, and parts of eastern Canada. In the aftermath of the disturbance, large portions of the Eastern Interconnection were blacked out, and several electrical islands were present. System operators faced a formidable task: to reassemble the grid and restore power to tens of millions of customers. The challenges that had to be overcome varied significantly from one state or province to another. New York, New England, Ontario, Michigan, and Ohio each had unique problems that operators had to address.