{
  "type": "FeatureCollection",
  "title": "Donner Party relief expeditions, 1847",
  "researched": "2026-09-27",
  "geometryBasis": "Interpretive links between representative historical places, not surveyed tracks. The four expeditions share a broadly documented corridor. Pixel offsets separate the lines visually without asserting different physical trails. Inward and return journeys are summarized by one corridor per expedition.",
  "waypoints": [
    {
      "id": "johnsons",
      "name": "Johnson’s Ranch area",
      "coordinates": [
        -121.287,
        39.025
      ],
      "note": "Western staging area on the Bear River, east of present Wheatland. Representative ranch-area point, not a surveyed adobe location.",
      "source": "https://ohp.parks.ca.gov/ListedResources/Detail/493"
    },
    {
      "id": "mule",
      "name": "Mule Spring",
      "coordinates": [
        -120.801,
        39.244
      ],
      "note": "A supply cache and transfer point from pack animals to travel on foot. Approximate location on Lowell Hill Ridge.",
      "source": "https://www.nps.gov/places/mule-spring.htm"
    },
    {
      "id": "bear",
      "name": "Bear Valley",
      "coordinates": [
        -120.704,
        39.292
      ],
      "note": "The reliefs used this mountain valley for staging and supplies. This is Bear Valley near Emigrant Gap; the exact winter route onward to the Yuba is uncertain.",
      "source": "https://www.donnerpartydiary.com/feb47.html"
    },
    {
      "id": "yuba",
      "name": "Yuba corridor",
      "coordinates": [
        -120.51,
        39.315
      ],
      "note": "Generalized passage through the upper South Yuba country. Contemporary accounts name crossings and camps without enough detail to fix every segment.",
      "source": "https://www.donnerpartydiary.com/mar47.html"
    },
    {
      "id": "starved",
      "name": "Starved Camp · approximate area",
      "coordinates": [
        -120.35,
        39.319
      ],
      "note": "A schematic point west of Donner Pass. The second relief was trapped here by a storm; the third encountered the stranded survivors. The exact campsite is not established by this map.",
      "source": "https://www.donnerpartydiary.com/mar47.html"
    },
    {
      "id": "pass",
      "name": "Donner Pass",
      "coordinates": [
        -120.325,
        39.316
      ],
      "note": "The Sierra crossing between the upper Yuba country and Truckee Lake. Relief lines generalize the snowbound approach rather than tracing exact footsteps.",
      "source": "https://www.donnerpartydiary.com/feb47.html"
    },
    {
      "id": "lake",
      "name": "Truckee Lake camps",
      "coordinates": [
        -120.235,
        39.325
      ],
      "note": "The principal lake-camp area, now at Donner Lake. Individual cabins occupied separate sites; this point represents the camp cluster.",
      "source": "https://www.donnerpartydiary.com/mar47.html"
    },
    {
      "id": "alder",
      "name": "Alder Creek camps",
      "coordinates": [
        -120.179,
        39.369
      ],
      "note": "The Donner families’ camp area. First, second, and fourth relief accounts support visits here. No definite third-relief branch is drawn because that visit is uncertain.",
      "source": "https://www.donnerpartydiary.com/apr47.html"
    }
  ],
  "features": [
    {
      "type": "Feature",
      "properties": {
        "id": "relief1",
        "number": 1,
        "name": "First relief",
        "leaders": "Reasin P. Tucker & Aquila Glover",
        "dates": "February–March 1847",
        "color": "#60d8ed",
        "offset": -12,
        "dash": "12 3",
        "arrival": "February 18–19",
        "summary": "Food reaches the camps at last. Rescuers visit the lake and Alder Creek, then escort a first group west across the snowy divide.",
        "inward": "Johnson’s Ranch → Mule Spring → Bear Valley → upper Yuba → Donner Pass → lake camps; a party continues to Alder Creek.",
        "outward": "Survivors return over the Sierra to Bear Valley and Mule Spring. The relief diary records arrival at Johnson’s Ranch on March 7.",
        "note": "Breen’s February 19 diary says the men arrived the previous evening; the relief diary dates arrival February 19. Both dates are retained here.",
        "events": [
          [
            "Feb 4–5",
            "Departure from Johnson’s Ranch; accounts differ by a day."
          ],
          [
            "Feb 18–19",
            "Arrival at the lake camps; visits to Alder Creek follow."
          ],
          [
            "Feb 22",
            "Return begins in the relief diary and Breen’s diary."
          ],
          [
            "Mar 7",
            "The relief diary records reaching Johnson’s Ranch."
          ]
        ],
        "sources": [
          {
            "label": "Breen and first-relief diaries · February",
            "url": "https://www.donnerpartydiary.com/feb47.html"
          },
          {
            "label": "First-relief return · March",
            "url": "https://www.donnerpartydiary.com/mar47.html"
          }
        ],
        "waypoints": [
          "johnsons",
          "mule",
          "bear",
          "yuba",
          "pass",
          "lake",
          "alder"
        ]
      },
      "geometry": {
        "type": "MultiLineString",
        "coordinates": [
          [
            [
              -121.287,
              39.025
            ],
            [
              -121.13,
              39.12
            ],
            [
              -121.01,
              39.18
            ],
            [
              -120.9,
              39.23
            ],
            [
              -120.801,
              39.244
            ],
            [
              -120.75,
              39.263
            ],
            [
              -120.704,
              39.292
            ],
            [
              -120.665,
              39.319
            ],
            [
              -120.58,
              39.32
            ],
            [
              -120.51,
              39.315
            ],
            [
              -120.43,
              39.322
            ],
            [
              -120.39,
              39.32
            ],
            [
              -120.35,
              39.319
            ],
            [
              -120.325,
              39.316
            ],
            [
              -120.29,
              39.326
            ],
            [
              -120.235,
              39.325
            ]
          ],
          [
            [
              -120.235,
              39.325
            ],
            [
              -120.2,
              39.344
            ],
            [
              -120.179,
              39.369
            ]
          ]
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "id": "relief2",
        "number": 2,
        "name": "Second relief",
        "leaders": "James F. Reed",
        "dates": "Late February–March 1847",
        "color": "#ffc85a",
        "offset": -4,
        "dash": "7 4",
        "arrival": "March 1",
        "summary": "Reed reaches the camps and his children. On the return, a storm traps the company west of the pass at the place remembered as Starved Camp.",
        "inward": "Johnson’s Ranch → Mule Spring → Bear Valley → upper Yuba → Donner Pass → lake camps and Alder Creek.",
        "outward": "The return divides: Reed and some survivors press west; others remain at Starved Camp and are brought out during the third relief.",
        "note": "March 1 follows Breen’s diary. Reed’s diary has inconsistent weekday/date headings, so its entries cannot all be treated as an exact calendar.",
        "events": [
          [
            "Late Feb",
            "Reed’s party ascends from Johnson’s Ranch via Mule Spring."
          ],
          [
            "Mar 1",
            "Breen records the arrival of ten men with provisions."
          ],
          [
            "Early Mar",
            "The return party is caught in a storm west of the pass."
          ],
          [
            "Mid-Mar",
            "The third relief assists the group left at Starved Camp."
          ]
        ],
        "sources": [
          {
            "label": "Reed’s approach · February diary",
            "url": "https://www.donnerpartydiary.com/feb47.html"
          },
          {
            "label": "Breen, Reed and the return · March accounts",
            "url": "https://www.donnerpartydiary.com/mar47.html"
          }
        ],
        "waypoints": [
          "johnsons",
          "mule",
          "bear",
          "yuba",
          "starved",
          "pass",
          "lake",
          "alder"
        ]
      },
      "geometry": {
        "type": "MultiLineString",
        "coordinates": [
          [
            [
              -121.287,
              39.025
            ],
            [
              -121.13,
              39.12
            ],
            [
              -121.01,
              39.18
            ],
            [
              -120.9,
              39.23
            ],
            [
              -120.801,
              39.244
            ],
            [
              -120.75,
              39.263
            ],
            [
              -120.704,
              39.292
            ],
            [
              -120.665,
              39.319
            ],
            [
              -120.58,
              39.32
            ],
            [
              -120.51,
              39.315
            ],
            [
              -120.43,
              39.322
            ],
            [
              -120.39,
              39.32
            ],
            [
              -120.35,
              39.319
            ],
            [
              -120.325,
              39.316
            ],
            [
              -120.29,
              39.326
            ],
            [
              -120.235,
              39.325
            ]
          ],
          [
            [
              -120.235,
              39.325
            ],
            [
              -120.2,
              39.344
            ],
            [
              -120.179,
              39.369
            ]
          ]
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "id": "relief3",
        "number": 3,
        "name": "Third relief",
        "leaders": "William Eddy & William Foster · John Stark",
        "dates": "March 1847",
        "color": "#ff91bd",
        "offset": 4,
        "dash": "2 4",
        "arrival": "March 13",
        "summary": "Eddy and Foster go on to the lake. John Stark stays with the stranded Breen and Graves group, helping bring them out of Starved Camp.",
        "inward": "Johnson’s Ranch → Bear Valley → upper Yuba → Starved Camp. Eddy, Foster, Thompson and Miller continue over the pass to the lake.",
        "outward": "The lake party starts back March 14; Stark brings the stranded group west. The parties converge along the Yuba and continue through Mule Spring.",
        "note": "The route branches in responsibility, not necessarily geography. A third-relief visit to Alder Creek is uncertain, so its line ends at the lake.",
        "events": [
          [
            "Mar 6",
            "Eddy and Foster leave Johnson’s Ranch in the compiled chronology."
          ],
          [
            "Mar 12",
            "The party encounters the survivors at Starved Camp."
          ],
          [
            "Mar 13–14",
            "Arrival at, and departure from, the lake camps."
          ],
          [
            "Mar 18",
            "Stark’s group reaches Mule Spring in the compiled account."
          ]
        ],
        "sources": [
          {
            "label": "Eddy’s account to Thornton and survivor recollections",
            "url": "https://www.donnerpartydiary.com/mar47.html"
          },
          {
            "label": "McGlashan · History of the Donner Party",
            "url": "https://www.gutenberg.org/ebooks/6077"
          }
        ],
        "waypoints": [
          "johnsons",
          "mule",
          "bear",
          "yuba",
          "starved",
          "pass",
          "lake"
        ]
      },
      "geometry": {
        "type": "MultiLineString",
        "coordinates": [
          [
            [
              -121.287,
              39.025
            ],
            [
              -121.13,
              39.12
            ],
            [
              -121.01,
              39.18
            ],
            [
              -120.9,
              39.23
            ],
            [
              -120.801,
              39.244
            ],
            [
              -120.75,
              39.263
            ],
            [
              -120.704,
              39.292
            ],
            [
              -120.665,
              39.319
            ],
            [
              -120.58,
              39.32
            ],
            [
              -120.51,
              39.315
            ],
            [
              -120.43,
              39.322
            ],
            [
              -120.39,
              39.32
            ],
            [
              -120.35,
              39.319
            ],
            [
              -120.325,
              39.316
            ],
            [
              -120.29,
              39.326
            ],
            [
              -120.235,
              39.325
            ]
          ]
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "id": "relief4",
        "number": 4,
        "name": "Fourth relief",
        "leaders": "William Fallon",
        "dates": "April 1847",
        "color": "#c1a0ff",
        "offset": 12,
        "dash": "15 4 2 4",
        "arrival": "April 17",
        "summary": "The final expedition reaches the camps, recovers property, and brings out Lewis Keseberg, the last survivor found there.",
        "inward": "Johnson’s Ranch → Bear Valley → upper Yuba → Donner Pass → lake camps → Alder Creek. The lower corridor is generalized through the same Mule Spring country.",
        "outward": "The published account describes a return across the pass with Keseberg and a descent to the lower end of Bear Valley to meet the horses on April 25.",
        "note": "The published “Fallon journal” has disputed authorship and contains accusations contested by Keseberg. The map uses its itinerary, not its allegations as established fact.",
        "events": [
          [
            "Apr 13",
            "Departure from Johnson’s Ranch in the published account."
          ],
          [
            "Apr 15",
            "Horses left at Bear Valley; the party continues on foot."
          ],
          [
            "Apr 17",
            "Lake cabins reached; the party continues to Alder Creek."
          ],
          [
            "Apr 25",
            "Horses met at lower Bear Valley on the return."
          ]
        ],
        "sources": [
          {
            "label": "Published fourth-relief account and Keseberg’s response",
            "url": "https://www.donnerpartydiary.com/apr47.html"
          },
          {
            "label": "McGlashan · later survivor testimony",
            "url": "https://www.gutenberg.org/ebooks/6077"
          }
        ],
        "waypoints": [
          "johnsons",
          "bear",
          "yuba",
          "pass",
          "lake",
          "alder"
        ]
      },
      "geometry": {
        "type": "MultiLineString",
        "coordinates": [
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            ],
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              -121.13,
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            ],
            [
              -121.01,
              39.18
            ],
            [
              -120.9,
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            ],
            [
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            ],
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            ],
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            ],
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            ],
            [
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            ],
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            ],
            [
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            ],
            [
              -120.39,
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            ],
            [
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            ],
            [
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            ],
            [
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            ],
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            ]
          ],
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            ],
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        ]
      }
    }
  ]
}