Nice example of Wilkes map from the US Ex. Ex., showing remarkable details throughout the region, with an inset of the Columbia River.
Wilkes' Oregon Territory is a major contribution to American cartography and was widely considered the most detailed map of the region north of the Sacramento River.
Willkes' map provided an accurate depiction of Oregon Territory, a thinly settled part of the United States as late as the 1840s. Wilkes supported the view of Senator Lewis Linn that the northwest boundary of America should be 54 deg. 40' North, the famous 54-40 or Fight controversy. This map was used to support his claim that was based on 'topographical' grounds, and was instrumental in setting the scene for American interests in the territory.
The map covers the region from Fraser's Fort and Fort St. James in British Columbia south to the upper Sacramento River, and from the Pacific coast to the Black Hills east of the Rocky Mountains. The map provides excellent detail of the region including dozens of forts, watershed, and other place names. A large inset map "Columbia River Reduced from a survey made by the U.S. ex. Ex. 1841" depicts the river from Ft. Walla Walla to its mouth, where one of Wilkes' ships, the Peacock, was lost on the infamous Columbia Bar. It includes details of missions, Indian villages, and the major mountains with north oriented to the left.
As noted by Wheat:
This map was in many respects the most detailed of this extensive area yet published, and for the main Oregon region and the Hudson's Bay Company territories to the north it was an accurate, really quite extraordinary, map . . . This map had much influence on the later maps of the area.
The map was quite popular and was used to illustrate several gold rush era overland guide books.