The 18th Independent Battery Indiana Light Artillery, also known as Lilly's Hoosier Battery and Lilly's Battery, was a civil war regiment formed in Indiana during the American Civil War. The regiment was formed at the end of 1860 by 22-year-old Eli Lilly, an Indianapolis pharmacist. He had recruitment posters placed around the city and recruited primarily among his friends and classmates. The unit were first issued 6 "Rodman Guns" and was manned by 156 men. The Battery members stated preference to 3" Ordnance Rifles over the 10 pound Parrott Rifle due to its tendency to bursting. The unit mustered in Indianapolis where it was drilled during 1861, excelling at their skill with firing accuracy. Lilly was elected captain of the unit in August 1862 when the unit was deployed to join the Lightning Brigade commanded by Col. John T. Wilder.

Eli Lilly was an American soldier, pharmacist, chemist, and businessman who founded the Eli Lilly and Company pharmaceutical corporation. Lilly enlisted in the Union Army during the American Civil War and recruited a company of men to serve with him in the 18th Independent Battery Indiana Light Artillery. He was later promoted to major and then colonel, and was given command of the 9th Regiment Indiana Cavalry. Lilly was captured in September 1864 and held as a prisoner of war until January 1865. After the war, he attempted to run a plantation in Mississippi, but it failed and he returned to his pharmacy profession after the death of his first wife.