In 1909 Rocky Mountain was formed from the western edge of Rosebud in the north part of the riding, the entire riding of Banff, the western half of High River and Macleod.

In 1940, the north part of the riding merged with Cochrane to form Banff-Cochrane.

Okotoks-High River expanded to fill the central portion of the riding and Pincher Creek expanded to fill the south end of the riding and became Pincher Creek-Crowsnest.

The riding ran the length of the Rocky Mountains along the Alberta / British Columbia border.

After the Alberta Legislature passed an Act increasing the number of seats from 25 to 41,[2] the Frank Paper described the Rocky Mountain constituency as a "monstrous gerrymander" which benefited labour interests.