LIVING SURVEY — measurements are reviewed continuously as new data and local evidence arrive. Seen a sign, a gate, or a better name? Submit an update no account needed · photos welcome via GitHub

Haleakala Highway

7116.4 m · net rise 383.4 m · total ascent 390.4 m · overall 5.4% · evidence quality A (high) · Makawao-Paia · Hawaii · share

Shape: sustained — 32% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 32 m.

Matches: Cycle to the Sun (Haleakalā hillclimb race) — course segment — Haleakalā Highway 377, Makawao Avenue to Crater Road.

Gradient ladder what do windows mean?

Window	Maximum	Located at
2 m (diagnostic)	17%	381–383 m
3 m (diagnostic)	16%	381–384 m
5 m	16%	380–385 m
10 m	15%	375–385 m
20 m	13.5%	366–386 m
25 m	12.8%	361–386 m
50 m	10.3%	337–387 m
100 m	8.2%	350–450 m

Measured on the mapped road line; moving the line 1 m either way reads 12.7–13.0% over 25 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.

Surface: paved throughout, according to each state's road inventory.

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

Route colour = gradient over a 25 m window: <10% 10–20% 20–25% ≥25%

Haleakala Highway LiDAR hillshade map with contours

Profile

The map, profile and gradient chart share one position — move your pointer over them and the marker follows. Colors are the gradient bands; the shaded span is the steepest 25 m. Any 25 m figure is good to about a point either way (why).

Measurement card

Elevation	USGS 3DEP (The National Map) — USGS 3DEP 1 m DEM, HI_NOAAMauiOahu_2020_B20 (collected 2020)
Resolution / CRS	1.0 m grid, EPSG:26904; sampled every 1.0 m, bilinear interpolation
Tiles	x77y231, x78y231
Road centreline	OpenStreetMap (local PBF extract), snapshot 2026-09-07T20:21:20Z
Quality status	evidence quality A; no review flags; no caveated windows
Analysis	OCL 0.1.0, analysis 0.1.0, run retro-box2-260909, calculated 2026-09-09

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:26904",
  "elevation_resolution_m": 1.0,
  "elevation_tiles": [
    "data/cache/usa/hi/USGS_1M_4_x77y231_HI_NOAAMauiOahu_2020_B20.tif",
    "data/cache/usa/hi/USGS_1M_4_x78y231_HI_NOAAMauiOahu_2020_B20.tif"
  ],
  "calculated_at": "2026-09-09T01:53:20+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/hawaii-2026-09-08-batch.osm.pbf",
  "osm_snapshot": "2026-09-07T20:21:20Z",
  "run_id": "retro-box2-260909",
  "elevation_provider": "USGS 3DEP (The National Map)",
  "elevation_licence": "Public domain \u2014 USGS 3DEP 1 m DEM, courtesy of the U.S. Geological Survey",
  "elevation_dataset": "USGS 3DEP 1 m DEM, HI_NOAAMauiOahu_2020_B20 (collected 2020)",
  "elevation_tile_ids": [
    "x77y231",
    "x78y231"
  ],
  "climb_origin": "discovered",
  "canopy_check": "unavailable \u2014 no surface model (DSM or point cloud) registered for this coverage",
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing"
}