Lake Minnewanka is a glacial lake in the eastern area of Banff National Park in Canada, about five kilometres northeast of the Banff townsite. The lake is 21 km long and 142 m deep, making it the 2nd longest lake in the mountain parks of the Canadian Rockies. The lake is fed by the Cascade River, flowing east of Cascade Mountain, and runs south through Stewart Canyon as it empties into the western end of the lake.