The Pioneers by David McCullough was a thorough book subtitled The Heroic Story of the Settlers Who Brought the American Ideal West.
McCullough recounts the Americans who left the Northeast in the late 1700s and settled on the banks of the Ohio River, effectively expanding the country westward.
The story is told through the tales of a few main characters, and later their offspring, who both set out on a tale of adventure, and played a pivotal role in establishing that part of the country as one free from slavery.
It wasn't necessarily a book I loved, but told well the story of an important time in American history prior to the Civil War.