The Humboldt meridian in California, longitude 124° 07' 10" west from Greenwich, intersects the base line on the summit of Mount Pierce at latitude 40° 25' 02" north (co-ordinates in NAD27 datum), and governs the surveys in the northwestern corner of California, lying west of the Coast Range of mountains, and north of township 5 south, of the Humboldt meridian system. This principal meridian was established in 1853.
- "California and Nevada". U.S. Bureau of Land Management. Retrieved 2012-09-28.
- "Cadastral Survey: Principal Meridians and Base Lines". U.S. Bureau of Land Management. Retrieved 2012-09-28.
- "Humboldt Meridian". The Center for Land Use Interpretation. Retrieved 2012-09-28.
- "Humboldt Principal Meridian, Scotia, CA". Principal Meridian Project. Archived from the original on 2013-01-25. Retrieved 2012-09-28.