Ultra Trail UK

Self-navigated running, UK

US Ultra Races Every UK Runner Should Know

Written by Catriona Adams. Published 8 September 2026

British runners already follow American ultras closely — Barkley Marathons alone draws more UK search interest than most races on this site. These five are the ones worth knowing: what they actually involve, how you'd realistically get a place, and how they compare to the self-navigated Rounds and organised races covered elsewhere here.

Why these five, and why now

Each of these races sits at a different point on the same spectrum this site already maps for the UK — from the Barkley Marathons, which pushes self-navigation further than any British Round, to Western States, the organised 100-miler that set the template most modern trail races still follow. Between them: Hardrock's altitude and lottery, Leadville's open entry and low finish rate, and Badwater's heat. Jasmin Paris — already on this site for her Ramsay Round record — is the clearest bridge: in 2024 she became the first woman ever to finish the Barkley.

The five races, side by side

RaceLocationDistanceElevationEntryNavigation
Barkley MarathonsTennessee~100 mi~25,000-27,000ftSecret application ritual — no lotteryMap & compass, no GPS
Western States 100California100.2 mi18,090ft ascentGolden Ticket races or lotteryFully marked course
Hardrock 100Colorado102.5 mi~33,000ftWeighted lottery, 146 placesMarked, high-altitude terrain
Leadville 100Colorado100 mi15,744ft combinedOpen lottery, no standard requiredMarked course
Badwater 135California135 mi~13,000ftInvitation-only, 100 placesMarked course, extreme heat

The five races covered here

  • Barkley Marathons — No GPS, no marked course, book pages as checkpoints — Tennessee's answer to a Round, taken to an extreme.
  • Western States 100 — 100.2 miles, California — the original organised 100-miler, first run in 1977.
  • Hardrock 100 — 102.5 miles above 11,000ft average elevation, Colorado — entry by weighted lottery only.
  • Leadville 100 — "Race Across The Sky" — Colorado, open entry, fewer than half the field usually finishes.
  • Badwater 135 — Death Valley to Mount Whitney Portal, 135 miles, up to 130°F — invitation-only.

FAQ

Frequently asked questions

Because UK runners already follow them closely — Barkley Marathons alone gets a bigger UK search audience than most British races on this site, and British runners have made real history at several of them. This page treats that interest directly rather than ignoring it.

The Barkley Marathons, by a wide margin — no marked course, no GPS, navigation entirely the runner's own. Jasmin Paris, who holds a Ramsay Round record on this site, became the first woman ever to finish it, in 2024.

Leadville 100 has the most open entry system — lottery, qualifying races, charitable donation, or a coaching programme, with no qualifying standard required. Hardrock and Badwater are the most restrictive, by weighted lottery and invitation respectively.

Western States 100 is a UTMB World Series qualifier, though UTMB itself runs a separate, competing race in the same region (Canyons Endurance Runs by UTMB).

Hardrock 100, at around 33,000ft over 102.5 miles — nearly double Western States' 18,090ft of ascent over a similar distance, driven by an average elevation above 11,000ft throughout.

Yes — most notably Jasmin Paris, who became the first woman ever to finish the Barkley Marathons in 2024. No British finisher or record-holder is documented for Badwater in the sources used across this cocon.

Each began as one person's idea, tested on themselves or a small group, before becoming an institution — Gordy Ainsleigh's solo 1974 run at Western States and Al Arnold's 1977 Badwater crossing are the clearest examples, echoing how the Rounds on this site started the same way.

Related

Barkley MarathonsNo GPS, no marked course, book pages as checkpoints — Tennessee's answer to a Round, taken to an extreme.Western States 100100.2 miles, California — the original organised 100-miler, first run in 1977.Hardrock 100102.5 miles above 11,000ft average elevation, Colorado — entry by weighted lottery only.Leadville 100"Race Across The Sky" — Colorado, open entry, fewer than half the field usually finishes.Badwater 135Death Valley to Mount Whitney Portal, 135 miles, up to 130°F — invitation-only.The British RoundsThe UK's self-navigated equivalent