K42 Villa La Angostura

The experience

Forty-two kilometres with 2,211 m of gain, the summit of Cerro Bayo at 1,800 m placed at km 31, and a six-hour cut at the base of the climb. Ninety-five percent of it is unpaved.

It is the closing race of the K42 Series, and the 2025 winners earned a start at the K42 Anaga Marathon in the Canary Islands. Over 2,000 runners come for the four-day week; the town of Villa La Angostura is the host, not a backdrop.

The K42 Adventure Marathon started in Villa La Angostura in 2003 and spawned the K42 Series, with races across Latin America and Europe. The 2025 edition, the 22nd, hosted Argentina's first national masters trail championship. In 2011 the race was run on ash from the Puyehue eruption.

Where the sources disagreeThis is a race, not a public route: the course crosses private land and the Cerro Bayo ski area and is marked only on race day. The organizer's 42K rules set a cut at the base of Cerro Bayo at 15:00, six hours after the 9:00 start; later runners are diverted around the summit on the scenic road and classified after everyone who finished the full course. Mandatory kit, 750 ml of fluid and a windbreaker or dry shirt, is imposed only if bad weather is forecast, and can be waived at the race briefing. The gain figure is from the 2024 edition and the course changes; the organizer publishes a KMZ file and an altimetry graph, not a number. The launch entry price for the 42K is 345,000 Argentine pesos, and foreign runners must contact the organizer for payment.