Horseshoe Pass
4543.0 m · net rise 275.7 m · total ascent 278.8 m · overall 6.1% · confidence: good
Shape: sustained — 32% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 109 m.
Matches: British National Hill Climb Championship, Wikipedia, 100 Greatest Cycling Climbs (Simon Warren) — 1971 venue, as Bwlch yr Oernant (Wikipedia championship venue list) — Venue 1971, 1976, 1981 (as Bwlch yr Oernant) and 2022 (The Old Shoe course) — Has its own article (Bwlch yr Oernant, Denbighshire) — No. 90 (official app, 2026 numbering).
≈ Overhead cover (tree canopy or structures) spans 11% of this route — detected by comparing the surface model (DSM, treetops and rooftops) against the terrain model (DTM, bare ground). Under cover the bare-ground model is built from fewer laser returns, so metre-scale readings can wobble; maxima whose window sits in a covered zone are marked ≈ below — less certain — the flag does not say whether the true value is higher or lower. Longer windows average over more clean ground and are steadier.
Gradient ladder what do windows mean?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | ≈23% | 985–987 m | under overhead cover |
| 3 m (diagnostic) | ≈18% | 985–988 m | under overhead cover |
| 5 m | ≈17% | 985–990 m | under overhead cover |
| 10 m | ≈15% | 980–990 m | under overhead cover |
| 20 m | ≈14.5% | 795–815 m | under overhead cover |
| 25 m | ≈14.4% | 795–820 m | under overhead cover |
| 50 m | ≈13.7% | 789–839 m | under overhead cover |
| 100 m | ≈12.7% | 764–864 m | under overhead cover |
may_start_earlier Extent detection suggests reviewing where this climb starts/ends.
Map
Check this route yourself: Google Maps route via their router · Street View at the base where coverage exists · geojson.io our exact measured line · OpenTopoMap
This climb's data: OCL JSON — the full gradient ladder, quality flags and provenance in the OpenClimb Ladder format.
Ridden it, or know better? Submit data for this climb no account needed
© OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap
Profile
Provenance
{
"analysis_version": "0.1.0",
"sample_interval_m": 1.0,
"interpolation": "bilinear",
"smoothing": "none",
"gradient_windows_m": [
5.0,
10.0,
20.0,
25.0,
50.0,
100.0
],
"diagnostic_windows_m": [
2.0,
3.0
],
"elevation_crs": "EPSG:27700",
"elevation_resolution_m": 1.0,
"elevation_tiles": [
"data/cache/wales/dtm_1m/wg_del_1_318345_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_318346_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_318347_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_318348_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_319345_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_319346_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_319347_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_319348_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_320345_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_320346_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_320347_20200326dtm.tif",
"data/cache/wales/dtm_1m/wg_del_1_320348_20200326dtm.tif"
],
"calculated_at": "2026-08-13T02:13:16+00:00",
"road_source": "wales-discovered-adopted-routes/horseshoe-pass.geojson",
"elevation_provider": "Welsh Government",
"elevation_dataset": "Welsh Government LiDAR 1m DTM (2020-2023)",
"elevation_licence": "Open Government Licence v3 \u2014 \u00a9 Crown copyright Welsh Government",
"elevation_catalogue_layer": "geonode:welsh_government_lidar_tile_catalogue_2020_2023",
"elevation_tile_ids": [
"wg_del_1_318345_20200326dtm.tif",
"wg_del_1_318346_20200326dtm.tif",
"wg_del_1_318347_20200326dtm.tif",
"wg_del_1_318348_20200326dtm.tif",
"wg_del_1_319345_20200326dtm.tif",
"wg_del_1_319346_20200326dtm.tif",
"wg_del_1_319347_20200326dtm.tif",
"wg_del_1_319348_20200326dtm.tif",
"wg_del_1_320345_20200326dtm.tif",
"wg_del_1_320346_20200326dtm.tif",
"wg_del_1_320347_20200326dtm.tif",
"wg_del_1_320348_20200326dtm.tif"
],
"elevation_capture_dates": [
"26-03-2020"
],
"route_summit_trim_m": 1292.0,
"route_summit_trim_loss_m": 61.1,
"climb_origin": "discovered",
"notes": "Coarse pass: max 10.6% over 200 m (Terrain 50), gain 130.1 m over 4680 m way. EXTENDED by graph walk: +7 segment(s) at base, +0 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 1 overlapping proposal(s): discovered-lane-52-9976-3-1928 ROAD-REVIEW: way 105260775: unnamed service way; way 105260775: service way, surface untagged ADOPTED (notable slice 2026-08-11): listed."
}