The family seat of the influential Carroll family of Maryland, Doughoregan Manor, began in 1702 with a seven-thousand-acre land grant from colonial proprietor Cecil Calvert to his attorney general Charles Carroll, who became the wealthiest man in Maryland. The house today is a sprawling three-hundred-foot-long, five-part Georgian residence of brick with a rough-cast finish, tetrastyle Doric porticoes front and rear, and an octagonal cupola, built as the centerpiece of a sprawling, slave-operated tobacco plantation. The main block began as a one-and-a-half-story dwelling with a gambrel roof characteristic of the Chesapeake house, flanked by detached kitchen and chapel buildings that later were joined by hyphens. The chapel was built when Catholic worship was prohibited, and for many years the family opened it to the local community for Sunday services. Additions and renovations made in the 1830s by grandson Charles Carroll V included the Greek Revival flourishes.
The manor encompasses an extensive array of outbuildings, many in stone, including a Gothic Revival cottage-style gatehouse (c. 1860; 3120 Manor Lane). Doughoregan Manor was designated a National Historic Landmark for its association with its third owner, Charles Carroll of Carrollton, the only Catholic signer of the Declaration of Independence. The house remains in the family.