POP–UP–RUNS / Tåsentier'n 10k 2026

Tåsentier’n is a free 10.32 km trail race in Oslo, run as part of the PopUpRuns series in the forests around Oslo and Bærum. It starts and finishes at Havnajordet, begins with a steep climb up Havnabakken, and packs 285 meters of climbing into a short course that is almost entirely off-road: 98% trail, with only small bits of gravel and asphalt. PopUpRuns has arranged informal trail races in Oslo since 2013, with a deliberately simple setup: no bib numbers, low barriers, and room for both beginners and experienced runners. The course heads from Havnajordet through forest toward Korsvoll, then uses trails around Langmyra, Svartkulp, Nedre Blanksjø, Høgåsen, Svenskemuren, Grinda, and back through Korsvollskogen to the finish. Runners encounter boggy ground, forest paths, slabs, dips, mud, descents, and some steeper stream-side sections rather than a polished road-race surface. Entry is free, the route is well marked, and timing is self-managed through Strava after registering on Fjelldatabasen, which produces the results list. Kristoffer Homdrom Fredriksen and Torstein Greni organize the series, supported by Salomon and Löplabbet, and runners are encouraged to pre-register so the post-race food can be planned, though the PopUpRuns idea still leaves space for people to show up on the day if their legs, the weather, and their mood line up.