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Old Maps of San Luis Obispo County, California for Metal Detecting

Plan your next treasure hunt with 599 historic maps of San Luis Obispo County. Find old homesites, ghost towns, trails, and gathering spots that may be lost to time — perfect for identifying promising metal detecting locations.

  • Locate forgotten sites: Uncover places like long-lost settlements, abandoned rail lines, or gathering spots.
  • Plan better hunts: Use map overlays combined with LiDAR or satellite views to narrow in on historically rich areas.
  • Made for detectorists: Thousands of hobbyists use these maps to discover relics, coins, and hidden history.

Use these historic maps to boost your research and find new opportunities beneath the surface of San Luis Obispo County.

San Luis Obispo County, CA maps

(599)
  1. 1897 Map of Port Harford
    1897 Map of Port Harford
    1897 Port Harford
    1897 Print · USGS
    Coastal San Luis Obispo County is captured here in the late nineteenth century, focusing on the maritime activity near the Pecho Mountain Range. Researchers can trace the early topography of Port Harford and local landmarks like Pt. San Luis and Whaler Id.
    3 unique versions available
  4. 1897 Map of San Luis Obispo
    1897 Map of San Luis Obispo
    1897 San Luis Obispo
    1897 Print · USGS
    Coastal California in the late nineteenth century centers on the vital Southern Pacific Line as it carves through the Santa Lucia Range. Genealogists and historians can trace the early city grid of San Luis Obispo and rural stops like Goldtree and Cuesta.
    4 unique versions available
  7. 1897 Map of Cayucos
    1897 Map of Cayucos
    1897 Cayucos
    1897 Print · USGS
    The central California coast is captured here in the late 1890s, when ranching and maritime trade centered on the village of Cayucos. Trace early property lines across San Bernardo or locate landmarks like Morro Rock and Hollister Peak.
    5 unique versions available
  10. 1897 Map of Arroyo Grande, 1903 Print
    1897 Map of Arroyo Grande, 1903 Print
    1897 Arroyo Grande
    1903 Print · USGS
    Coastal San Luis Obispo County comes alive in the late nineteenth century as the railroad transforms old ranchos into bustling seaside towns. You can trace early industrial sites like the Asphalt Mines or locate historic coastal points such as Mallagh Landing and Sycamore Springs.
    5 unique versions available
  13. 1900 Map of San Luis
    1900 Map of San Luis
    1900 San Luis
    1900 Print · USGS
    Coastal California at the turn of the century shows a landscape where rail lines like the Pacific Coast Ry met the sea. Trace early industrial sites like the Asphalt Mines or follow the coast from Morro Rock to the pier at Port Harford.
    4 unique versions available
  16. 1902 Map of Santa Ynez
    1902 Map of Santa Ynez
    1902 Santa Ynez
    1902 Print · USGS
    Santa Barbara County at the turn of the century was a land of high mountain meadows and isolated ranching outposts. Genealogists can trace family holdings at Cuyama Ranch or follow old trails through Salisbury Potrero and the San Rafael Mountains.
  19. 1903 Map of Mt. Pinos
    1903 Map of Mt. Pinos
    1903 Mt. Pinos
    1903 Print · USGS
    Ventura and Kern counties at the start of the century remain largely a wild backcountry of forest reserves and high peaks. Genealogists and historians can trace early outposts like Pattiway, the high-altitude Frazier Borax Mine, and the Pine Mtn Lodge.
    7 unique versions available
  22. 1905 Map of Guadalupe
    1905 Map of Guadalupe
    1905 Guadalupe
    1905 Print · USGS
    The Central California coast at the dawn of the century reveals a landscape shaped by the Southern Pacific R. R. and coastal trade. Genealogists and historians can trace rail-side settlements like Betteravia, Casmalia, and the old maritime Pt. Sal Landing.
    6 unique versions available
  25. 1905 Map of Santa Ynez
    1905 Map of Santa Ynez
    1905 Santa Ynez
    1905 Print · USGS
    The Santa Barbara backcountry is shown here at the start of the twentieth century, focusing on the high ridges and canyons of the San Rafael Mountains. Genealogists and hikers can trace early routes through San Marcos Pass or locate old sites like Wasioja and the Montgomery Potrero.
    5 unique versions available
  28. 1905 Map of Lompoc
    1905 Map of Lompoc
    1905 Lompoc
    1905 Print · USGS
    Santa Barbara County at the turn of the century reveals a landscape of historic ranchos and early industry before the rise of modern development. Researchers can trace the early Pacific Coast RR and locate heritage sites like Santa Ynez Mission and the Union Oil Wells.
    7 unique versions available
  31. 1910 Map of Buena Vista Lake, 1912 Print
    1910 Map of Buena Vista Lake, 1912 Print
    1910 Buena Vista Lake
    1912 Print · USGS
    The southern San Joaquin Valley comes to life in the years before the great lakes were drained for agriculture. Genealogists and historians can trace early rail stops like Bowerbank and Hazelton or locate rural landmarks such as the Palm School and Moron Taft P O.
  34. 1912 Map of McKittrick
    1912 Map of McKittrick
    1912 McKittrick
    1912 Print · USGS
    Kern and San Luis Obispo counties are shown here just as the early oil boom and cattle ranching were shaping the desert landscape. Researchers can trace the original Pacific Southern rail lines and find legacy ranch sites like Sandiego Joe's and Temblor Ranch.
    4 unique versions available
  37. 1912 Map of Buena Vista Lake, 1921 Print
    1912 Map of Buena Vista Lake, 1921 Print
    1912 Buena Vista Lake
    1921 Print · USGS
    The San Joaquin Valley at the height of its irrigation and oil boom is captured here, from the streets of Bakersfield to the shores of Buena Vista Lake. Genealogists and local historians can trace early schools like Old River School and the rail stops of the Sunset RR.
    4 unique versions available
  40. 1914 Map of Cholame
    1914 Map of Cholame
    1914 Cholame
    1914 Print · USGS
    Central California ranching and rugged topography meet at the turn of the century across the Temblor Range. Genealogists and historians can trace early outposts like Devils Den, Dudley, and Carter's Ranch.
  43. 1915 Map of Cholame, 1956 Print
    1915 Map of Cholame, 1956 Print
    1915 Cholame
    1956 Print · USGS
    The ranchlands of the Central Coast and western San Joaquin Valley were still largely defined by mining and cattle during the early 1900s. Genealogists and researchers can trace family-run operations at Cholame Ranch or find vanished rural schoolhouses like Eagle School and Alliance School.
  46. 1917 Map of Cholame
    1917 Map of Cholame
    1917 Cholame
    1917 Print · USGS
    San Luis Obispo and Monterey counties in the early twentieth century reveal a landscape of remote quicksilver mines and isolated ranching outposts. Genealogists and researchers can trace family-named landmarks like Carter's Ranch and early rural education at Eagle School or Choice Valley School.
    4 unique versions available
  49. 1919 Map of San Miguel
    1919 Map of San Miguel
    1919 San Miguel
    1919 Print · USGS
    The Salinas River valley comes alive in this late 1910s survey of the Monterey and San Luis Obispo borderlands. Genealogists can trace a remarkable network of rural schoolhouses, including Eagle, Vineyard, and Monroe, alongside the historic Imusdale Cemetery.
    4 unique versions available
  52. 1919 Map of Bryson
    1919 Map of Bryson
    1919 Bryson
    1919 Print · USGS
    Monterey and San Luis Obispo counties appear here at the end of the Great War, showing a ranching landscape defined by the San Antonio and Nacimiento rivers. Researchers can locate remote schoolhouses like Pinkerton School and the high-elevation Quicksilver Mine.
    5 unique versions available
  55. 1919 Map of Paso Robles
    1919 Map of Paso Robles
    1919 Paso Robles
    1919 Print · USGS
    San Luis Obispo County in the late nineteen-teens shows a landscape where the railroad spurred the growth of cattle and grain hubs. Researchers can trace the layout of Paso Robles or find rural landmarks like San Miguel Mission and Geneseo School.
    5 unique versions available
  58. 1919 Map of Bradley
    1919 Map of Bradley
    1919 Bradley
    1919 Print · USGS
    The Salinas River valley comes alive in the late 1910s, showing the early railroad era in Monterey County. Genealogists can trace family-named sites like Williams Ranch and schools like Hames Valley School or Nacimiento School.
    4 unique versions available
  61. 1919 Map of Adelaida
    1919 Map of Adelaida
    1919 Adelaida
    1919 Print · USGS
    San Luis Obispo County’s interior ridges are mapped here shortly after the Great War, showing a landscape of small ranches and rural schools. Genealogists can trace family connections to landmarks like Adelaida, the German Church, and the Williams Ranch.
    2 unique versions available
  64. 1919 Map of Piedras Blancas
    1919 Map of Piedras Blancas
    1919 Piedras Blancas
    1919 Print · USGS
    The northern San Luis Obispo coast appears just before the age of modern highway development, centered on the Piedras Blancas Lighthouse. Researchers can locate early rural infrastructure like the Washington School and trace coastal landmarks from Pt Sierra Nevada to Arroyo del Corral.
    2 unique versions available
  67. 1919 Map of San Simeon
    1919 Map of San Simeon
    1919 San Simeon
    1919 Print · USGS
    The San Luis Obispo coast during the late 1910s reveals a landscape of cattle ranches, early maritime landings, and upland mining. Genealogists and historians can trace family-named sites like the Hearst Ranch, Old Castro House, and the Olmstead School.
    4 unique versions available
  70. 1921 Map of Cape San Martin
    1921 Map of Cape San Martin
    1921 Cape San Martin
    1921 Print · USGS
    The Big Sur coast and its remote mining interior are documented here during the early twenties, prior to the construction of the modern highway. Local historians can trace family operations like the Krenkels Ranch or investigate the gold-mining era at the Los Burros Mine and the Calizona Mines.
    6 unique versions available
  73. 1922 Map of Pozo
    1922 Map of Pozo
    1922 Pozo
    1922 Print · USGS
    San Luis Obispo County backcountry reveals its rural school network and forest boundaries in the years following the Great War. Genealogists and local historians can trace the locations of the El Dorado School and Highland School near the settlement of Pozo.
    3 unique versions available
Showing maps 1-25 of 599

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Frequently asked questions

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