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Built on bad decisions in Boulder, CO.

Arc of Attrition

4 Race Events50 Mile, 50K, Half Marathon, 100 Mile

UTMB

Porthtowan, England, United Kingdom

Course map for Arc of Attrition Arc 100K

Arc of Attrition Arc 100K

Jan 23, 2027

50 Mile

Course map for Arc of Attrition Arc 100M

Arc of Attrition Arc 100M

Jan 22, 2027

100 MileCrew

Course map for Arc of Attrition Arc 20K

Arc of Attrition Arc 20K

Jan 24, 2027

Half Marathon

Course map for Arc of Attrition Arc 50K

Arc of Attrition Arc 50K

Jan 24, 2027

50K