As a young adult, Boone supplemented his farm income by hunting and trapping game, and selling their pelts in the fur market. Through this work, Boone first learned the easy routes westward. Despite some resistance from Native American tribes such as the Shawnee, in 1775, Boone blazed his Wilderness Road from North Carolina and Tennessee through Cumberland Gap in the Cumberland Mountains into Kentucky. There, he founded the village of Boonesborough, Kentucky, one of the first American settlements west of the Appalachians. Before the end of the 18th century, more than 200,000 Americans migrated to Kentucky/Virginia by following the route marked by Boone.
Boone served as a militia officer during the Revolutionary War (1775–83), which, in Kentucky, was fought primarily between the American settlers and British-allied Native Americans, who hoped to expel the Americans. Shawnee warriors captured Boone in 1778. He escaped and alerted Boonesborough that the Shawnee were planning an attack. Although heavily outnumbered, Americans repelled the Shawnee warriors in the Siege of Boonesborough. Boone was elected to the first of his three terms in the Virginia General Assembly during the Revolutionary War, and he fought in the Battle of Blue Licks in 1782. Blue Licks, a Shawnee victory over the Patriots, was one of the last battles of the Revolutionary War, coming after the main fighting ended in October 1781.