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Constitution Hill

347.9 m · net rise 60.6 m · overall 17.4% · confidence: high · Abertawe · West Glamorgan · share

Shape: sustained — 30% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 287 m.

Matches: Wikipedia, 100 Greatest Cycling Climbs (Simon Warren) — Constitution Hill, Swansea — has its own article — No. 100 (verified in the official 100 Climbs app, 2026 numbering) — the series finale is in Swansea.

Gradient ladder what do windows mean?

Window	Maximum	Located at
2 m (diagnostic)	24%	309–311 m
3 m (diagnostic)	24%	309–312 m
5 m	23%	309–314 m
10 m	22%	307–317 m
20 m	21.9%	161–181 m
25 m	21.9%	309–334 m
50 m	21.6%	297–347 m
100 m	21.2%	81–181 m

may_continue_beyond_end 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.

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

Constitution Hill 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_21_264193_20220113dtm.tif"
  ],
  "calculated_at": "2026-08-12T09:06:25+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/wales-2026-08-11.osm.pbf",
  "osm_snapshot": "2026-08-10T20:21:40Z",
  "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_21_264193_20220113dtm.tif"
  ],
  "elevation_capture_dates": [
    "13-01-2022"
  ],
  "climb_origin": "discovered",
  "notes": "Coarse pass: max 19.6% over 200 m (Terrain 50), gain 52.4 m over 266 m way. EXTENDED by graph walk: +2 segment(s) at base, +0 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. ADOPTED (notable slice 2026-08-11): clean-steep.",
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing.html"
}