Nice example of this seminal map of the West.
Shows Spanish Trail, Cooke's Wagon Route, Kearney's Route, Lewis & Clarke's Canoe Route, Oregon Route, early roads, towns, Indian Tribes, mining claims, mountains, rivers, etc. No Lake Tahoe. Massive Tule Lake. Early California Counties shown. Pre-Gadsden purchase border with Mexico. Early forts located, especially in Oregon Territory.
Nice topographical detail after Fremont, although still very conjectural in the Great Basin. Dominated by massive counties which extend the width of UT. Only the western counties of OR & WA appear.