Doughoregan Manor is a plantation house and estate located on Manor Lane west of Ellicott City, Maryland, United States. Established in the early 18th century as the seat of Maryland's prominent Carroll family, it was home to Founding Father Charles Carroll, a signer of the United States Declaration of Independence, during the late 18th century. A portion …Doughoregan Manor is a plantation house and estate located on Manor Lane west of Ellicott City, Maryland, United States. Established in the early 18th century as the seat of Maryland's prominent Carroll family, it was home to Founding Father Charles Carroll, a signer of the United States Declaration of Independence, during the late 18th century. A portion of the estate, including the main house, was designated a National Historic Landmark on November 11, 1971. It remains in the Carroll family as a private working farm.