Canada Day officially replaced Dominion Day in 1982.
The change applied to the July 1 holiday, which commemorates the creation of Canada through the British North America Act, now called the Constitution Act, 1867. The first national celebration was held in 1868, and a federal law made July 1 a statutory holiday in 1879, initially calling it the “anniversary of Confederation.” The name Dominion Day became common afterward.
The official renaming took place on October 27, 1982. It followed the enactment of the Canada Day legislation during a period when Canadian institutions and public celebrations were placing greater emphasis on a distinct Canadian identity. The date of the holiday did not change: Canadians still celebrate on July 1.
A common mix-up is to treat 1967 as the renaming year. That was Canada’s centennial, marking 100 years since Confederation. Another is 1980, when “O Canada” became the national anthem. Dominion Day was officially replaced by Canada Day in 1982, although people may still encounter the older name in historical references.