Lebanon is a city in and the county seat of Boone County, Indiana, United States. The population was 16,662 at the 2020 census. Lebanon is located in central Indiana, approximately 29 miles (47 km) northwest of downtown Indianapolis and 36 miles (58 km) southeast of Lafayette.

Lebanon was officially established on April 30, 1830. It was named by a pioneer settler who saw a stand of hickory trees on the site and was reminded of the Biblical cedars of Lebanon. The first post office at Lebanon was established in 1832. In 1853, Lebanon was incorporated as a town and later became a city in 1875.

Lebanon is the home of the Historic Cragun House. Built in 1893, it was once the home of Strange Nathaniel Cragun and his family. The family travelled the world, and their house is now a living history museum full of the pieces they collected from their travels as well as original furniture from the dwelling. This Victorian home is owned and maintained by the Boone County Historical Society and serves as headquarters for the organization. The Cragun House has been added to the National Register of Historic Places.

Also listed on the National Register of Historic Places are the Boone County Courthouse and Oak Hill Cemetery.

According to the 2010 census, Lebanon has a total area of 15.566 square miles (40.32 km²), of which 15.55 square miles (40.27 km²) (or 99.9%) is land and 0.016 square miles (0.04 km²) (or 0.1%) is water.

The county courthouse of Lebanon is notable for its single-piece vertical Ionic order limestone columns. They were at one time believed to be the largest single-piece limestone columns in the world.

As of the 2020 census, Lebanon had a population of 16,662. The median age was 39.1 years. 22.4% of residents were under the age of 18 and 18.0% of residents were 65 years of age or older. For every 100 females there were 95.6 males, and for every 100 females age 18 and over there were 91.8 males age 18 and over.

97.2% of residents lived in urban areas, while 2.8% lived in rural areas.