How come Ottawa doesn't have it's own capital district like most capital cities?

Question

This is something that I'm sorta curious about but not losing sleep over. Ottawa is a city in Ontario, not in its own district, such as Washington, DC or Mexico City, D.F. (Distrito Federal). I could presume that this is a Commonwealth theme, as Canada was a British possession. But I now realize that in another ex-U.K. possession, Australia, Canberra is in it's own district, nee ACT (Australian Capital Territory) I presume. Do u guys got some info?

Answer 1

Usually, a country creates a capital district because they do not want any particular state or province to have control over the capital city.

One guess is that the Canadians didn't feel this was necessary and were not worried about it.  

Another possibility is that the city is actually older than the country.  In the US's case, the government actually "created" Washington DC after it was already a country.  For Canada, Ottawa was already a city in Ontario and was just chosen to be the capital.  (Probably because it was halfway between Montreal and Toronto, the two largest cities.)

Answer 2

Why should that be necessary ?