From 1867 until 1982, July 1st was celebrated across the land, "from sea to sea, and from the river unto the ends of the earth," as Dominion Day.
That changed in 1982. Dominion Day died at the hands of a few misguided social engineers.
Andrew Cohen, in The Unfinished Canadian (2007) relates the story:
In 1982, we did away with Dominion Day. Just like that. A member of parliament decided it was a colonial remnant, an insult to Quebec and multicultural Canada. So, one Friday afternoon in July, when the House of Commons was almost empty, it passed a seemingly innocuous private member's bill ("An Act to Amend the Holidays Act") changing the name of the national holiday celebrated on July 1 from Dominion Day to Canada Day.
At that moment there were only 13 members present in the House. Parliamentary rules stated that 20 members were required for a quorum. However, none of the 13 asked for a count, and the speaker unilaterally declared the quorum. The short "debate" focused on such nonsense as "Dominion" sounding too colonial, too Anglo centric. (Imagine if they had actually clued into the fact that it might have been "too Judeo-Christian".) The bill passed in about five minutes. The Senate "rubber stamped" the legislation the following autumn.
"They happily went about their historic cleansing," Cohen notes. "Dominion Day became Canada Day, a term of crushing banality." In concluding his point, Cohen lashes at the absurdity of this sort of ahistorical, social-engineering revisionism, condemning it as "a renunciation of the past, a misreading of history, laden with political correctness and historical ignorance."
I wonder if Sir Leonard Tilley would have approved.