Lake Middleton is a 24-hectare picturesque lake at the southwest corner of Lake Ōhau. It is slightly higher than and separated from the main lake by a narrow strip of land. Lake Ōhau Road runs between the lakes, with a DOC campsite. Immediately to the north, on a rise overlooking Lake Middleton, is Lake Ōhau Alpine Village. The west, mountain-facing side is largely farmland with scattered tussocks.
There is road access to the lake from Lake Ōhau Road at the south end of the lake. There is a parking area and boat ramp by the campsite. There is also access at the north end below the village. Walking access is limited to the area around the access roads.
The lake is most popular during summer for boating and trout fishing. A wide range of water birds can also be seen around the lake.