Bladensburg is an unincorporated community on the border between the Clay and Jackson Townships of Knox County, Ohio, United States. Although it is unincorporated, it has a post office, with the ZIP code of 43005. It lies along State Route 541 east of Martinsburg. Bladensburg is home to East Knox Elementary School. The school serves students in kindergarten through sixth grade, including those with special needs. Bladensburg is the home of a popular annual Christmas parade, which has been held since 1971.