Ohio County, Indiana naturalizations were recorded in:

• Court Order Books
• Probate Court Order Books
• Separate naturalization volumes

Online databases:

• Ohio County Naturalization Books 1848-1927
• Ohio County Naturalizations from Court Records, 1844-1854

Microfilm:

• Family History Library (1848-1927)

Books:

• An Index to Naturalization Records in Pre-1907 Indiana County Courts. Indiana Historical Society : Indianapolis, 2001.