Statement of Significance (as of designation - January 20, 1961):
South Pass was the easiest passage through the Rocky Mountains and heavily used by westbound settlers, fur traders, and miners in the 19th century. The traffic through the Pass helped establish an effective U.S. claim to the Pacific Northwest.

Condition:
The National Historic Landmark is generally in good condition with the 19th century setting well preserved. However, the site is facing a number of developmental pressures.

Currently the Bureau of Land Management is processing applications for two mining operations within the pass. Additionally, a gold testing program approved last year has the potential to result in gold mining in the area, if commercially viable deposits can be found. A recent geophysical project has resulted in increased applications for permits to drill in areas adjacent to South Pass and could result in applications within the National Historic Landmark. There is a proposal to build a cloud-seeding tower within the National Historic Landmark area. This feature could dominate much of the landscape, if approved. Increasing tourism continues to be a potential threat to the conditions of the ruts. Additional range development could insert elements out of character to the NHL in the area. The Bureau of Land Management continues to work with all parties to minimize potential impacts to the NHL. However, activities under the 1872 Mining Act and the exercise of valid and existing leases by their owners are not subject to cancellation. The lack of an approved boundary for the NHL makes it difficult to manage the site for inappropriate development.