[2] In 1787, the fledgling United States defined the Northwest Territory, which included the area of present-day Indiana.

Starting in 1794, Native American titles to Indiana lands were extinguished by usurpation, purchase, or war and treaty.

This included the future Boone County, designating areas covered by the Delaware New Purchase.

[5] The interim county commissioners met on May 1 of the following year to identify a permanent seat of government, which by law had to be within 2 miles (3.2 km) of the county's center; the [future] city of Lebanon was selected to serve this purpose.

Its central position, excellent soil, and available water power have been in its favor.

[7] The highest point of the county (984 feet (300 meters) ASL) is a small hill two miles/3.2 km northeast of Lebanon.

The commissioners execute acts legislated by the council, collect revenue, and manage the county government.

The judge on the court is elected to a term of four years and must be a member of the Indiana Bar Association.

[18] County Officials: The county has other elected offices, including sheriff, coroner, auditor, treasurer, recorder, surveyor, and circuit court clerk.

In 2024, Vice President Kamala Harris became the first Democratic presidential candidate since Lyndon B. Johnson to win a share of over forty percent of the vote.

As of the 2010 United States Census, there were 56,640 people, 21,149 households, and 15,509 families in the county.