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Cnoic agus lough

This is a looped-course mountain run and open water swim challenge. Cnoic agus Lough starts and finishes near the eastern beach of Glendalough's Upper Lake. It includes a 12k/700m mountain run section followed by a 1k lake swim.  

Lake & Derrybawn.jpg
Lake from South.jpg


Cnoic agus Lough begins at the 'Crosses' monument at the green near Glendalough's Upper Lake. It's runner's route choice for the mountain run section. Derrybawn and Mullacor summits, plus The Spinc's footbridge (crossing Gleneola River), must be hit in that order. The run finishes just off The Miners' Road on the northwest shore of The Upper Lake at a specific lake entry point (see below required checkpoints). Athletes finish their loop with a 1km swim of the Upper Lake. The swim finishes when the athlete reaches the eastern beach. The challenge is complete when the athlete reaches the 'Crosses' mounument.

required checkpoints

1. The 'Crosses' monument 111 962 (Circlular low - walled structure, 100m east of the Eastern Beach)

2. Derrybawn Summit (476m) 119 954

3. Mullacor Summit (661m) 093 939

4. Spinc Footbridge 076 962

5. Lake Entry Point 098 962 

6. The Upper Lake, Glendalough, Eastern Beach 110 963

7. The 'Crosses' monument 111 962 (Circlular low - walled structure, 100m east of the Eastern Beach)

upper lake from piers.jpg

Rules & Guidelines

  • Athletes must carry coat, hat, gloves, foil blanket, first aid kit, whistle, map/compass and/or gps for the mountain section.

  • Athletes must hit all checkpoints in the specified order. Lake entry is only at the specified checkpoint. No athlete should enter the lake from the western shore or any other area. 

  • Swim gear must be clean and dry. Fins are not allowed. Wetsuits, booties and gloves are permitted. 

  • Tow float and whistle are mandatory for swim.

  • An observer must walk and observe the swimmer from the lake trail for the duration of the swim. SUPs, kayaks and other boats are not permitted on the lake.

  • Athletes must announce their attempt to IMC, prior to their challenge start. 

  • GPS devices are allowed and pacers are allowed. The same pacer(s) can not complete the length of the challenge with the athlete. Otherwise, it will be considered a team completion.

  • Completed challenges will be validated when athlete supplies IMC with a gpx of their run/swim. 


This is a personal challenge. IMC's only involvement is to agree to record attempts. Neither IMC, its servants or agents can accept any responsibility of any nature or kind for loss, damage or injury suffered by a participant who takes part or attempts Cnoic agus Lough. Participants are responsible for ensuring that they have sufficient fitness and experience to attempt this challenge. Mountain running and cold open water swimming pose risks such as injury, death, hypothermia and cold water shock. IMC can accept no responsibility for participant's safety, injury or loss. Each participant takes part at their own risk and is fully responsible for their own safety, support and equipment. By attempting this challenge the participant is accepting the disclaimer and rules in full. 

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