[3] The companies' counties of origin included Jefferson, Bartholomew, Daviess, Howard, Henry, Jennings, Jackson, and Hamilton.

The Regiment was officially mustered into United States service for a period of three months on April 25, 1861.

Sent on to the town of Webster, they arrived on June 2 and marched 14 miles (23 km) that same night to Philippi.

Among its line officers was Captain Jeremiah C. Sullivan, who would later rise to the rank of brigadier general.

[citation needed] The total strength of the 6th Indiana Infantry at the time of its organization in April 1861 was 782 men, including 37 commissioned officers.