Martinsburg is an unincorporated community in Jackson Township, Washington County, in the U.S. state of Indiana.
Martinsburg was founded in 1818 by Dr. Abner Martin, and named for him.
A post office was established at Martinsburg in 1830, and remained in operation until it was discontinued in 1919.
Martinsburg is located at .
The United States Census Bureau defined Martinsburg as a census designated place in the 2022 American Community Survey.