The Great Western Railway was a railway that operated in Canada West, today's province of Ontario, Canada. It was the first railway chartered in the province, receiving its original charter as the London and Gore Railroad on March 6, 1834, before receiving its final name when it was rechartered in 1845.
At its peak, the Great Western system stretched 1,371 kilometres (852 mi) with its main operating base in Hamilton. The city at the head of Lake Ontario was pivotal in opening up the unpopulated and heavily wooded interior of what was then known as Canada West. A substantial part of its revenue was from serving as a bridge line between the New York Central and Michigan Central Railroads, making it significant in North American history. Its lines remain in use, part of Canadian National Railway's network.