Lebanon is the county seat of Warren County, Ohio. In 1800, Ichabod Corwin became the town's first resident even though Lebanon did not officially exist until 1802. The community had 1,327 residents in 1840. The principal reason for its growth was Lebanon's location on the Warren County Canal and along three improved roads connecting Lebanon with Dayton, Columbus, and Cincinnati. The Little Miami Railroad also passed within four miles of the town. By 1846, six churches, two newspaper offices, fifteen stores, one gristmill, two sawmills, and a woolen factory were in the town.
Over the next forty years, Lebanon continued to prosper. In 1890, 3,174 people lived in the town. Two years earlier, the town contained three newspapers, nine churches, and one bank. The city directory for 1886 listed no manufacturing businesses in Lebanon. The National Normal University, founded in 1855, had nearly two thousand students enrolled. The University was closed in 1917,
Local people who find employment in Warren County usually work in sales, service, or manufacturing industries. Many residents also find seasonal work at the Paramount King's Island amusement park at nearby King's Mills, Ohio. In recent years, Lebanon increasingly has become a commuter town. Many of its 16,962 residents in 2000 worked in surrounding communities.