Martinsburg is a village in Knox County, Ohio, United States.

Martinsburg was founded in 1828 when the nearby rival towns of Hanover and Williamsburg merged.

[4] According to the United States Census Bureau, the village has a total area of 0.18 square miles (0.47 km2), all land.

33.0% of all households were made up of individuals, and 16.5% had someone living alone who was 65 years of age or older.

About 21.6% of families and 14.0% of the population were below the poverty line, including 10.3% of those under the age of eighteen and 28.6% of those 65 or over.