Beinn Udlamain has a long north-south orientated summit ridge which stays above the 970 metre contour for over 1.5 kilometres. This ridge continues to the south to a col with a height of 809 metres which links to the adjacent Munro of Sgairneach Mhòr. In the opposite direction this ridge swings NE to link to A' Mharconaich which lies three km distant. Beinn Udlamain's slopes consist mostly of grass and heather with very little rock but they do drop steeply to the west towards Loch Ericht and to the east to the valley of the Allt Coire Dhomhain. On the northern side of the mountain are two grassy corries, the Glas-choire and the Fraoch-choire, which both drain NW into Loch Ericht. The mountain is crossed by an ancient line of iron fence posts which mark the old boundary between Perthshire and Invernesshire, this can be an aid to navigation in poor visibility.