Adamstown is an unincorporated community and census-designated place (CDP) in Frederick County, Maryland, United States. It is named for Adam Kohlenberg (March 11, 1819 – January 1, 1868), a station agent and first town merchant who owned much of present-day Adamstown. As of the 2010 census, the Adamstown CDP had a population of 2,372.

Adamstown lies in the fruitful valley amid Sugarloaf and Catoctin Mountain upon the former Carrollton Manor, a 17,000-acre (69 km) estate originally owned by Charles Carroll of Carrollton. Until 2000, it was a little-altered representative of mid-19th century linear town planning. It is significant in architecture for its variety of structures, including residential, commercial, industrial, educational, agricultural, and religious buildings. The late 18th century road from Jefferson to Greenfield Mills upon the Monocacy River, originally called the Bridal Road, followed the route of the present-day Mountville Road. The 1832 coming on of the railroad to the manor created the economic and transportation impetus for the early payment of the community.

Adamstown was first known as “Davis’ Warehouse” because Dr. Meredith Davis, a leading Quaker county miller, built a warehouse roughly 1835 where Mountville Road, by next called Jefferson Road, crossed the Baltimore & Ohio Railroad (9 miles (14 km) southwest of Frederick) to collection flour from his Greenfield Mills. The first settler in Adamstown was Robert Palmer, an African American “post and railer” who then ran a general store concerning 1835. In 1840 following Adam Kohlenburg was appointed the first B&O railway agent, the community became known as “Adamstown”, after his given name. He was plus the first postmaster and ran a general growth located in the lot along with his brick Italianate-style home and the railroad. Edward Hebb laid off lots on the north side of the railroad in the 1840s. Daniel Rhodes of Pennsylvania, the first white settler, was hence impressed when the location, he bought a tract of estate and laid it off into 12 building lots upon the south side of the railroad in 1856.

With Adamstown located so near to the Potomac River and Virginia, its citizens were regarding exclusively loyal to the South during the Civil War; however, both Federal and Confederate troops were each time moving upon Carrollton Manor. For several months in the spring of 1861, the Minute Men of Adamstown, a secession militia company composed of three officers (Captain Robert H. E. Boteler, 1st Lieutenant Jacob G. Thomas, and 2nd Lieutenant William Hilleary Johnson, all local doctors) planted a pole and flew the Confederate flag next to their guard post next to the B&O railroad. Many skirmishes in the charge were fought here and the town was often raided, most notoriously by the 43rd Battalion Virginia Cavalry, also known as Mosby’s Rangers, on July 30 and October 14, 1864. On one of these raids, Adam Kohlenburg’s entire growth was taken. Local folklore holds that one relatives had a son proceedings for the North and one war for the South.