There are 2 books in the The Frontiersmen series. The newest book is Wilderness Empire which came out in 1985.

1
The Frontiersmen

Book cover of The Frontiersmen
The frontiersmen were a remarkable breed of men. They were often rough and illiterate, sometimes brutal and vicious, often seeking an escape in the wilderness of mid-America from crimes committed back east. In the beautiful but deadly country which would one day come to be known as West Virginia, Kentucky,…
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2
Wilderness Empire

Wilderness Empire
Whipped to a frenzy by the French, the Iroquois  were cutting a swath of desolation from New York to  Virginia. Terrified settlers banded together, no  match for the Indians' cunning. Cabins were  burned, entire families massacred, victims scalped,  captives tortured. Yet, in the end, the Iroquois  would pay the highest…