Ironman Traverse (V4) is one of the most famous boulder problems in the Buttermilks area near Bishop, California.

This long, low, pumpy lip traverse has become a rite of passage for visiting climbers.

The line follows an obvious, proud rail along the front face of the boulder, starting on the far left and moving rightward across incut edges, with heel hooks and body tension required to keep momentum. At around seven metres of sustained movement, it’s long for a boulder problem, and delivers a proper forearm burn — hence its reputation as a testpiece of endurance at the grade.

It’s considered a true Bishop classic because it’s accessible, photogenic, and climbs beautifully: the holds are clean and obvious, the movement is aesthetic, and the problem is equally fun for climbers projecting V4s, and for stronger climbers linking laps. The boulder sits in the middle of the Buttermilks’ stunning high-desert landscape, with the Sierra Nevada as a backdrop, making it as scenic as it is iconic.

Most climbers visiting Bishop will end up at the Iron Man Boulder at some point — whether to test themselves on the traverse, warm up on the easier variations, or just soak in one of the most famous pieces of stone in American bouldering.

First Ascent: Tony Puppo (1978).