Why was Manitoba originally called a postage stamp-sized province?

Manitoba was originally referred to as a "postage stamp-sized" province because of its extremely small geographic footprint when it was first created by the Manitoba Act in 1870.12

At the time of its entry into the Canadian Confederation, the province consisted of little more than the Red River Settlement. This limited size was a stark contrast to the vast North West Territory that surrounded it, which remained under the control of the federal government. The small boundaries were established following negotiations between the Canadian government and a provisional government led by Louis Riel, which had formed during the Red River Rebellion to protect the land and cultural rights of the Métis people.123