The 1st Battalion, Canadian Mounted Rifles, CEF, was an infantry unit of the Canadian Expeditionary Force in the First World War. Originally a mounted infantry unit named the 1st Regiment, Canadian Mounted Rifles, CEF, it was formed on November 7, 1914, in Brandon, Manitoba. Part of the 1st Brigade Canadian Mounted Rifles, the unit landed in France on September 22, 1915, where the conditions of the Western Front made its mounts more of a hindrance than a benefit. On January 1, 1916, both CMR brigades (six regiments) were dismounted, converted to infantry and reorganized as the 8th Infantry Brigade (four battalions). The 1st Regiment, CMR, became the 1st Battalion, CMR, and it absorbed half the personnel of the 3rd Regiment, CMR (the other half going to the 2nd Battalion, CMR).
The battalion fought in most of the 3rd Canadian Division's engagements until the end of the war.
The 1st CMR, along with the 4th CMR, was manning the 3rd Division's front on June 2, 1916, when the Germans launched their assault at the outset of the Battle of Mount Sorrel. Its positions were overrun, and 557 of its 692 members (80%) were killed, wounded or captured.
The battalion was rebuilt over the summer, and it was one of the first Canadian Corps units to attack when the corps shifted to the Somme. On September 15, 1916, the 1st CMR was in the first wave attacking Mouquet Farm. Although the attack gained ground, the Canadians did not take the strong point, but the assault was considered a successful diversion from the main attack on Courcelette.
The battalion was disbanded on November 15, 1920.
Perpetuation of the 1st Battalion, CMR, was initially assigned to the Manitoba Mounted Rifles and the Saskatchewan Mounted Rifles. The Manitoba Mounted Rifles converted to artillery in 1946 as the 118th Medium Battery, RCA (in Fort Frances) and this battery was virtually disbanded (see Supplementary Order of Battle) in 1965. The Saskatchewan Mounted Rifles merged into the 16th/22nd Saskatchewan Horse in 1936, which converted to infantry in 1941 as the Battleford Light Infantry (16th/22nd Saskatchewan Horse). This regiment merged into the Prince Albert and Battleford Volunteers in 1946, which in turn became part of the North Saskatchewan Regiment (Machine Gun) in 1955. This infantry regiment (now simply "The North Saskatchewan Regiment") continues to perpetuate the battle honours and traditions of the 1st Battalion, Canadian Mounted Rifles.