The Apex Mountain map area is located in the central part of the Dawson Range. Apex Mountain is the highest summit reaching an elevation of 2000 m. Upland topography changes from rounded summits throughout much of the southern half of the map area to more rugged terrain in the north part of the map area where the Dawson Range divide is located. Most of the map area is drained by the Klotassin River and Somme Creek. A cluster of streams near Apex Mountain drain northward into the Selwyn River or Hayes Creek.