BETA — measurements and names under active refinement. Seen a sign, a gate, or a better name? Submit an update no account needed · photos welcome via GitHub

Ceunant Gorddinan to Ffridd-y-Bwlch

2266.0 m · net rise 129.7 m · total ascent 134.2 m · overall 5.7% · confidence: high · Ceunant Gorddinan · Clwyd · share

Shape: sustained — 41% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 108 m.

Found purely from mapping and LiDAR data, and not yet matched against books, race records or lists — it may be well known to locals under a name we've never heard. It was cross-checked against the OS road network, surface models and map tags, but a discovery can still be an artifact of the terrain model or the map. Treat it as a well-evidenced hypothesis until someone has ridden it. If you know this road, tell us what you found — photographs, corrections and local knowledge all welcome; the map links below let you scout it first.

Gradient ladder what do windows mean?

Window	Maximum	Located at
2 m (diagnostic)	14%	691–693 m
3 m (diagnostic)	13%	690–693 m
5 m	13%	703–708 m
10 m	12%	698–708 m
20 m	11.8%	690–710 m
25 m	11.6%	685–710 m
50 m	11.3%	681–731 m
100 m	10.9%	656–756 m

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.

Measured, not vetted. This page records what the laser record shows about the road's shape — nothing more. Nobody has necessarily ridden or inspected this road for the survey, and a page here is not a recommendation and no guarantee that the road is open, surfaced, rideable or safe. Gates, private sections, missing rights of way and hazards do not show up in elevation data. Check access and conditions on the ground and make your own judgment.

Ridden it, or know better? Submit data for this climb no account needed · Share this climb

Ceunant Gorddinan to Ffridd-y-Bwlch LiDAR hillshade map with contours

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_11_269350_20210302dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_11_270350_20210302dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_11_271350_20210302dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_17_269348_20210330dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_17_269349_20210302dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_17_270348_20210330dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_17_270349_20210302dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_17_271348_20210330dtm.tif",
    "data/cache/wales/dtm_1m/wg_del_17_271349_20210302dtm.tif"
  ],
  "calculated_at": "2026-08-13T02:13:56+00:00",
  "road_source": "trunk-adopted-routes/discovered-lane-53-0227-3-9374.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_11_269350_20210302dtm.tif",
    "wg_del_11_270350_20210302dtm.tif",
    "wg_del_11_271350_20210302dtm.tif",
    "wg_del_17_269348_20210330dtm.tif",
    "wg_del_17_269349_20210302dtm.tif",
    "wg_del_17_270348_20210330dtm.tif",
    "wg_del_17_270349_20210302dtm.tif",
    "wg_del_17_271348_20210330dtm.tif",
    "wg_del_17_271349_20210302dtm.tif"
  ],
  "elevation_capture_dates": [
    "02-03-2021",
    "30-03-2021"
  ],
  "route_summit_trim_m": 297.2,
  "route_summit_trim_loss_m": 19.2,
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 9.3% over 200 m (Terrain 50), gain 43.3 m over 1602 m way. EXTENDED by graph walk: +1 segment(s) at base, +0 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. ADOPTED (trunk sweep, Peter's on-sight verdict 2026-08-12): clean table, adopt-all. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (53.0227, -3.9374)'.",
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing.html"
}