How much of the US has not been explored yet?

While much of the United States has been mapped and surveyed, there are still remote areas, particularly in regions like Alaska, the wilderness of the Pacific Northwest, and certain national parks, that remain relatively unexplored in terms of detailed scientific study and biodiversity assessment. It's estimated that several million acres of land may still hold undiscovered species and ecological insights. However, the concept of "exploration" can vary, as many areas have been visited but not extensively studied or documented. Overall, while the majority of the U.S. is known, there are still significant opportunities for discovery.