經過數次立憲會議之，1867年憲法法案於1867年7月1日通過，加拿大省、新不倫瑞省、新斯科省三個英屬北美殖民地組成加拿大聯邦。加拿大獲得羅伯特領地和西北部地區的控權，將兩者并州成西北地區，這一舉動促使該地區的原住民梅蒂人在1870年7月動紅河起義建立從西北地區分離出的馬尼托巴省。
1871年，不列顛哥倫比亞省（不列顛哥倫比亞殖民地與溫哥華島殖民地已在1866年并州）加入聯邦。兩年，愛德華王子島也加入聯邦。
首任總理約翰·亞山大·麥唐納及他的保守政府設立關稅以保護加拿大新生的製造業。為開西部，加拿大政府資助三項橫加鐵路項目（包括加拿大太平洋鐵路），配自治領土地法 ，開始對大平原的開。為維護這片新開區域的治安，加拿大政府設立西北山地警察局。1898年掀起的朗代淘金熱為加拿大西北領地帶來大批移民，這一事件直接促使這片區域從西北領地分離建立育空地區。在加拿大自由的總理威爾弗德·勞雷爾的領導下，歐洲移民開始在大平原地區定居，因此促成艾伯塔省和薩斯喀徹溫省在1905年建立。
Following several constitutional conferences, the Constitution Act officially proclaimed Canadian Confederation on July 1, 1867, initially with four provinces: Ontario, Quebec, Nova Scotia, and New Brunswick. Canada assumed control of Rupert's Land and the North-Western Territory to form the Northwest Territories, where the Métis' grievances ignited the Red River Rebellion and the creation of the province of Manitoba in July 1870. British Columbia and Vancouver Island (which had been united in 1866) joined the confederation in 1871, while Prince Edward Island joined in 1873. In 1898, during the Klondike Gold Rush in the Northwest Territories, parliament created the Yukon Territory. Alberta and Saskatchewan became provinces in 1905. Between 1871 and 1896, almost one quarter of the Canadian population emigrated southwards, to the U.S.
To open the West and encourage European immigration, Parliament approved sponsoring the construction of three transcontinental railways (including the Canadian Pacific Railway), opening the prairies to settlement with the Dominion Lands Act, and establishing the North-West Mounted Police to assert its authority over this territory. This period of westward expansion and nation building resulted in the displacement of many Indigenous peoples of the Canadian Prairies to "Indian reserves", clearing the way for ethnic European block settlements. This caused the collapse of the Plains Bison in western Canada and the introduction of European cattle farms and wheat fields dominating the land. The Indigenous peoples saw widespread famine and disease due to the loss of the bison and their traditional hunting lands The federal government did provide emergency relief, on condition of the Indigenous peoples moving to the reserves. During this time, Canada introduced the Indian Act extending its control over the First Nations to education, government and legal rights.