The incumbent PC premier Jim Prentice called an election on April 7, 2015, following the reveal of a new budget to strengthen his party's mandate. On election night, the NDP won 54 seats, re-electing all four of their incumbents as well as 50 new members to the legislative assembly. The NDP had expected to do well in Edmonton. Not only was Notley from an Edmonton riding, but Edmonton has historically been friendlier to centre-left parties than the rest of Alberta. However, in a result that exceeded even the most optimistic NDP projections, the party took every seat in the capital. It also swept the cities of Red Deer and Lethbridge, and took 15 seats in Calgary, the Tories' power base for four decades. They also won 16 additional seats in the rest of Alberta, mostly in the northern and central parts of the province.
