Canadian Government Railways (CGR) was the descriptive name used between 1915-1918 for all federal government-owned railways in Canada. The principal component companies were: the Intercolonial Railway of Canada (IRC), the National Transcontinental Railway (NTR), the Prince Edward Island Railway (PEIR), and the Hudson Bay Railway (HBR). There were also several minor branch railways in the province of New Brunswick.

The deepening financial crisis in Canada's railway industry toward the end of the First World War saw the majority of major railways across the country nationalized by the federal government.

The first system to be taken over was the bankrupt Canadian Northern Railway (CNoR) on September 6, 1918 whereby the government-appointed Board of Management for CNoR was instructed to take responsibility for all CGR operations as well.

Later that year, a Privy Council order issued on December 20, 1920 created the Canadian National Railways (CNR) as a means to simplify the funding and administration of the nationalized railway system.

The Grand Trunk Pacific Railway (GTPR) was nationalized after defaulting on loan payments March 7, 1919 and entered the CNR fold on July 12, 1920. GTPR's parent company, the bankrupt Grand Trunk Railway (GTR) was nationalized on May 21, 1920 and was absorbed into the CNR on January 30, 1923

The CGR moniker ceased to be used after 1918 but the CGR itself existed on paper until the late 20th century, largely due to real estate leases and other agreements. A Privy Council order dated July 22, 1993 authorized the sale of CGR to the Crown corporation CN for one dollar (CDN).