Americans following my twitter account may be confused as my Canadian friends are arguing about when Canada became a country. Why? Because it is a wee bit complicated. The government of Canada is celebrating 2017 as Canada's 150th birthday! Woot! Partaaay!
Why? Because the British North America Act is the fundamental starting point for this country, even if ... it was not entirely sovereign at that time. Others would focus on 1917, when Canada commanded its own troops in a pivotal battle, Vimy. Others might say 1939 since Canada entered World War II separately from the UK (a couple of days later). Correlates of War types say it is 1920 because prior to that the British did stuff like negotiate boundaries with the US. Others say 1967 because, um, reasons. 1982 is the most recent date that one could consider to be Canada's independence day, as the constitution was patriated or repatriated--Queen Elizabeth sent the constitution back to Canada, where Canadians could amend it without any involvement of the British parliament (I think, not all of this was in the citizenship guide). Also, 1982 is when Canada passed the Charter of Rights and Freedoms, akin to the US Bill of Rights, that is now a key part of the Canadian constitution (along with that British North American Act).
Americans reading that paragraph should be super-confused. After all, the US has a single date--July 4th, 1776. Ooops, the Declaration of Independence was adopted on that date, but not signed until a month later. And, oh yeah, the US was not actually independent until the Revolutionary War was won--either 1781 when Cornwallis surrendered at Yorktown or 1783 when the official end of the war, marked by the Treaty of Paris. But the US as we know it is really about the Constitution, which was negotiated in 1787 but only ratified in 1788. Alas, the US remained only half-free until 1865 with the end of the Civil War. Some would argue that the Civil War only ended in 1965 with the Civil Rights Movement and Voting Rights Act. So, perhaps the Americans should embrace Canada's confusion for its own?
This all turns on what does it mean to be Canada or to be the United States, what does it mean to be a country and what does it mean to be independent. If it is about independence, for the US, the date really is 1781--when the British lost the war even if it took some time for everyone to recognize that fact (if it were about democracy, the US argument should center on 1865 or 1965, but even 1920--if it is about women's suffrage). But things remain tricky for Canada, since Canada did not become completely independent in 1867. What it did become in that year is a big spot on the map with a set of rules to largely but not entirely govern itself. And it means that there will be heaps of parties this year and free entry to Canada's parks, so I guess we can stick with 1867 as the answer even if it is not entirely satisfying to history pedants.