Important early survey map, covering the region between Crescent City and San Francisco Bay, showing the results of R.S. Williamson and H.L. Abbot's surveys in Oregon and California, in anticipation of the location of the first transcontinental railroad.
Portions of the map includes a portion of the Emigrant Trail, Warner's Route in 1849, several Williamson Routes, and Major Wessel's Route in 1852.the routes travelled by many place names, watershed details and fine hachure in the mountainous areas. The balance of the map is mostly in skeletal format with an area to the west noted as not explored 'instrumentally.' Details numerous explorations and names the survey crews. Locates the Emigrant Trail plus the earlier explorations of Warner and Williamson in 1849, and Wessell in 1852. Notes the place Warner was killed by Indians in 1849, during early reconnaissances with R.S. Williamson.