Brewer Buttress climbs the corner to the left of E...
Description
There are many routes on Castle Mountain (see http://www.tabvar.org/ for excellent topos) but by far the most popular are Brewer Buttress and Eisenhower Tower. All (most?) routes face south for the most part.
The rock is typical Rockies limestone, meaning that it can be loose and crumbly, although the steeper/difficult sections tend to be quite solid.
Getting There
Castle Mountain is the obvious peak located at Castle Junction, about midway between Lake Louise and Banff. A hostel and campgrounds are nearby. All routes can be climbed in a day from the campground (or even from Calgary), although there is a really cool hut located on the peak which makes for a really short approach.