The rectangular system of public land surveys over the public
domain provides a simple and certain form of land identification
and legal description. It has been used continuously since Congress
passed the Land Ordinance of 1785 on May 20, 1785. Shortly
thereafter the U.S. General Land Office (now the Bureau of Land
Management) began surveying our young country using the Public Land
Survey System which is still in use today. The GLO Surveyors
established Meridian and Base Lines for the Public Land Survey
System, many of those Meridian and Base Lines were used to create
survey control for multiple states from a single mountain top.
Mount Diablo is one such mountain top and holds a special place
in U.S. land surveying history. Rising above the valleys east of
San Francisco, its 3,849-foot peak is visible throughout the Bay
Area. Mount Diablo's summit is the "Initial Point," the north/south
meridian, and east/west baseline intersection point that is the
basis for the establishment of land boundaries throughout most of
Northern California and all of Nevada.
This mountain of such modest elevation might seem unremarkable
when compared to the snow-capped Sierra Nevada's, however because
Mount Diablo stands alone, it has captured the attention of
explorers, sightseers, surveyors and now geocachers.
Cache is not at the posted coordinates, to find the cache you will
need to determine BLM's 1973 published coordinates for the Mount
Diablo Initial Point. From BLM's coordinates, add the sum of the
4th digit in the year that the Humbolt Initial Point was
established to the 4th digit in the year that Col. Leander Ransom
established the Mount Diablo Initial Point to the west coordinate.
Now subtract the 4th digit in the year that R.D. Cutts established
a different survey mark from the 4th digit in the year that the
Washington Initial Point was adopted and add that sum to BLM's
north coordinate.
Cache is located within a State Park and only available during
normal operating hours of the park. There is an admission fee to
the park so plan your day accordingly.