A challenging, 15km walk with almost 700m climbing, which took almost 6 hours. Parked beside Lough Keel (parking for 1or possibly 2 cars) and ascended directly up the heathery slope of Grogan More.Great views towards Errigal from top and also back over the lough to the SW. The next leg to Crocknafarragh doesn’t require much climbing but a lot of it is through peat hags and boggy terrain, before this peters out for more rocky/grassyground as you approach Crocknafarragh and its unlisted SE top.The views in all directions are tremendous. Dropping down to a col to the east, the ascent of Crockglass requires less than 50m climbing, and the views to the east over Lough Attirrive are spectacular.From there we turned south towards Addernymore, which was the most disappointing summit of the day – a giant lump of peat essentially - and the ascent from the north, while a mere 40m or so, was through energy-sapping peat hags. The top is marked by a small, solitary rock on a heathery mound. We then dropped down into the valley to the west and followed the stream for a couple of kilometres before veering west to pick up the tarred road again.This section was through grassy/occasionally boggy ground and challenging at times, but doable. While its never great to finish with a 4km road walk, this particular road offers stunning views over Lough Ascardan and Lough Keel.My fellow walkers, who were ahead of me (as usual) kindly returned in the car and saved me the final 1km, which explains why the loop isn’t quite complete, but I was very grateful to see that car pull up!