[2] Olallie Lake is open to vehicle traffic June to September.

[4] Mill Creek on the eastern shore is the only outflow, and once had a small dam to help keep water levels constant.

[2] Other lakes include Triangle, Lower, First, Head, Horse Shoe, Spoon, Surprise, Fish, Giffords, View, Top, Fork, Upper, Timber, Red, Averil, Wall, Sheep, and countless more.

[2] The glaciated region is roughly 89% forested with Noble fir, western hemlock, cedar species, pacific silver fir, mountain hemlock and several other tree species.

Recreation includes camping at Forest Service improved campgrounds, cabins and yurts at the Olallie Lake Resort.