Founded in 1669, Dorchester County was a thriving agricultural and maritime settlement during the colonial period. Court was being held in the county seat of Cambridge as early as 1695. A brick courthouse built during the 1770s burned in 1852, prompting city officials to set about commissioning a replacement on the same site. Richard Upjohn, the prominent Boston architect, provided plans for a new Italianate government building. His composition included characteristic features of the style such as a square tower placed asymmetrically, round arch openings, and wide eaves with bracketed gables. Upjohn was best known for his ecclesiastical architecture, as well as his skilled use of a variety of mid-nineteenth-century revival modes. By choosing a renowned architect, Dorchester County officials signaled the economic importance of Maryland’s lower eastern shore in the antebellum era.
Dorchester County Courthouse has a three-part front elevation, with each corner accented by quoins. The recessed center section has three, round arch doorways on the ground floor outlined by thick moldings springing from pilasters. The north section is a three-story tower with a low, pyramidal roof while the two-story south section shares a shallow hipped roof with the center. The brick is painted yellow with strong horizontal lines provided by belt courses at each floor.
While the original Upjohn design is still apparent on the exterior, extensive interior renovations took place in the twentieth century, particularly during the 1930s. These changes, which favored a Georgian Revival approach, were overseen by Baltimore architect William F. Stone Jr. and included additions to the southeast elevation of Upjohn's original structure.