In the Central Region, Aberdeen is located in Harford County 32 miles NE of Baltimore near Havre De Grace on US 40. Aberdeen is the site of the 75,000 acre Aberdeen Proving Ground, established in 1917 to develop and test ordance under simulated combat conditions. Outdoor displays about the federal reservation include foreign and U.S. artillery and tanks. Visitor information is available at the main gate on Hwy 22.