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Old Center Harbor Road

483.6 m · net rise 60.7 m · overall 12.6% · evidence quality A (high) · Meredith · New Hampshire · share

Shape: sustained — 31% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 128 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 state road inventory, OpenStreetMap and the point-cloud evidence for a graded road bed, 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?

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.

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

Access: Re-lined 2026-09-15 to the state road inventory where the measured line had left the road: the steepest 25 m now reads 22.64 % (was 28.91 %) and sits 0.0 m from the mapped centreline. Ranked on the re-measured line.

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

Load the interactive map

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

Topo (contours) Vector Aerial   © OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap · aerial imagery USGS (public domain)

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

Provenance

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    "crs": "EPSG:26919",
    "elevation_provider_key": "usa3dep",
    "authority": "usa-inventory",
    "registry_pbf": "new-hampshire-260822.osm.pbf",
    "tile_index_snapshot": "sha256:45488100ed3084c3"
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  "gradient_windows_m": [
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  "diagnostic_windows_m": [
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  "elevation_crs": "EPSG:26919",
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  "elevation_tiles": [
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    "data/cache/usa/nh/USGS_one_meter_x30y485_NH_CT_RiverNorthL6_2015.tif"
  ],
  "calculated_at": "2026-09-22T00:14:50+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "output/valley-260921/us/batch-usa-nh-chunk000.pbf",
  "osm_snapshot": "",
  "run_id": "remeasure-valley-260921-us",
  "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, NH_CT_RiverNorthL6_2015 (collected 2015)",
  "elevation_tile_ids": [
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  ],
  "route_base_cut_m": 317.0,
  "climb_origin": "discovered",
  "canopy_source": {
    "kind": "ept_corridor_max_return",
    "ept_source": "https://usgs-lidar-public.s3-us-west-2.amazonaws.com/USGS_LPC_CT_River_Lot6_Winnipesaulee_2015_LAS_2017",
    "ept_crs": "EPSG:3857",
    "station_coverage": 0.994,
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  },
  "structure_own_ways": 1,
  "structure_own_ways_source": "map-matched to the road network: the entry carried no way list, so the ways the route runs along were found by geometry (ukclimb.batch.own_ways_by_geometry)",
  "prior_doc": {
    "slug": "old-center-harbor-road",
    "calculated_at": "2026-09-15T06:56:54+00:00",
    "code_git_sha": null,
    "analysis_version": "0.1.0",
    "run_id": "reline-campaign-260915",
    "path": "/root/uk-climbs/output/valley-260921/us/priors/old-center-harbor-road/old-center-harbor-road.json",
    "spans": 1,
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  "carriageway": {
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    "width_max_m": 12.0,
    "bounded_share": 0.192,
    "unbounded_share": 0.808,
    "confidence_median": 0.0,
    "width_median_bounded_m": 3.5,
    "window_m": [
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    ],
    "width_at_max25_m": 3.75,
    "window_stations": 7,
    "single_track": false,
    "single_track_rule": "PROVISIONAL (2026-09-15): width_p10_m <= 3.0 m with bounded_share >= 0.6; recorded, not a rule",
    "status": "ok",
    "source": "dtm",
    "station_m": 25.0,
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    "stations_failed": 0,
    "hedge_to_hedge": {
      "status": "unavailable \u2014 no DSM raster (surface model absent or point-cloud only, which cannot serve off-line samples)"
    }
  },
  "remeasured": {
    "on": "2026-09-22",
    "why": "valley-crossing extent re-measure 2026-09-22: low-to-summit (317.0 m -> 801.0 m)",
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}