Bing found the following results
Early American Frontier - U.S. National Park Service
Cumberland Gap National Historical Park (U.S. National Park Service)
American frontier - Exploration, Expansion, Pioneers | Britannica
Thomas Cresap and Maryland’s Colonial Frontier - U.S.
4 Routes to the West Used by American Settlers - ThoughtCo
Cumberland Pioneer Settlers Atlas Volume I
American pioneer - Wikipedia
Wilderness Road - Map, Daniel Boone, Cumberland Gap | HISTORY
The Cumberland Road - National Geographic Society
Pioneer - Definition, Meaning & Synonyms | Vocabulary.com