Greensboro is a town located on the banks of the Choptank River in Caroline County, Maryland, United States. The population was 1,931 at the 2010 United States Census. The ZIP code is 21639. The primary phone exchange is 482 and the area code is 410. The town is served by Maryland Routes 480 and 313. Greensboro hosted the Caroline County Softball League, which produced both state and national champions. Willow Grove was listed on the National Register of Historic Places in 1972.