In the early morning hours of January 28, 2025, American Erin Ton set out from the Aconcagua base camp at Plaza del Mulas and up the slopes of the highest peak in South America, and in just over a quarter-day’s work, she returned to base camp with a new women’s unsupported fastest known time of 6:33 on the Argentinian mountain.
Erin Ton at the top of Aconcagua. All photos courtesy of Erin Ton.
Her time beat the previous women’s supported fastest known time (FKT) of 8:17, set by Lenka Poláčková of Slovakia in January 2025. According to Ton, “There were murmurs around camp that the actual time had been set by a guide at 7:35 round trip, so this was the time to beat.”
Ton’s ascent time of 4:50 also sets a new standard, eclipsing the 7:58 set by fellow American Rachel Boim in 2023, in a supported effort. Ton says, “I felt great starting off, reaching well above Camp 2 in only two hours. From there, the route was all new to me, and I could definitely feel the altitude.” She spent almost 10 minutes at the summit before heading down.
The view from the summit of Aconcagua.
High-Altitude Adventures
Ton is no stranger to FKT efforts, and at 22,841 feet (6,961 meters), Aconcagua is the highest peak on which she’s set a new mark. It’s the second-highest peak in the world outside of Asia and one of the seven summits — a collection of the highest peaks on each continent. The standard route up the mountain is considered non-technical, and from base camp, where Ton started, it gains about 8,500 feet (2,600 meters). The shortest variation, which can be used in good snow conditions, is about 8.7 miles (14 kilometers) roundtrip.
Ton had a great weather window for her run and says, “It was a cold morning, so I brought all the layers I had with me, but I quickly warmed up on the climb.” She ended up not using all the layers she’d started with and found it getting hot on the descent with the sun radiating off the snow. She says, “Overall, it was a great day in the mountains, even though I know I could shave off a lot of time if I were more acclimated and with less snow.”
Erin Ton at the Aconcagua base camp.
Ton has been in South America since early December, training for the effort. As part of her acclimation to the high elevation, Ton set a handful of FKTs on other mountains, including Illiniza Norte at 16,818 feet (5,126 meters), Cotopaxi at 19,347 feet (5,897 meters), and Rucu Pichincha at 15,400 feet (4,694 meters) — all peaks in Ecuador.
Chasing FKTs
According to the Fastest Known Time website, Ton has set 179 FKTs, with her run on Aconcagua currently being verified as her 180th and 181st. In the U.S., Ton is perhaps best known for her self-supported public-lands-only Colorado 14ers FKT, in which she climbed 57 of the 58 Colorado peaks over 14,000 feet (4,267 meters), skipping the privately owned Culebra Peak. Driving herself between peaks, she accomplished the feat in 14 days, 10 hours, and 9 minutes. Ton also holds several women’s FKTs in Nepal.
Erin Ton on the way to a new women’s FKT on Aconcagua.
If one reads into the statement on her Instagram post about her run in Aconcagua that says “1/7 summits done,” it seems a fair guess that FKTs on the other six highest peaks in the world are in her goals.
But for now, she’s resting for a few days and going for the longer version of the FKT on the Aconcagua, which starts much lower and is a 40-mile (65 kilometers) round-trip route with 13,250 feet (4,038 meters) of elevation gain. We’ll update this article if she’s successful on this second effort.
