The Lac-Mégantic rail disaster occurred in the town of Lac-Mégantic, Quebec, Canada, on July 6, 2013, at approximately 1:14 a.m. EDT, when an unattended 73-car Montreal, Maine and Atlantic Railway (MMA) freight train carrying Bakken Formation crude oil rolled down a 1.2% grade from Nantes and derailed downtown, resulting in the explosion and fire of multiple tank cars. Forty-seven people were killed. More than thirty buildings in Lac-Mégantic's town centre were destroyed, and all but three of the thirty-nine remaining buildings had to be demolished due to petroleum contamination. Initial newspaper reports described a 1 km (0.6-mile) blast radius.

The Canadian Pacific Railway, also known simply as CPR or Canadian Pacific and formerly as CP Rail (1968–1996), was a Canadian Class I railway incorporated in 1881. The railway was owned by Canadian Pacific Railway Limited, which began operations as legal owner in a corporate restructuring in 2001.