Ellicott City is an unincorporated community and census-designated place, along with being the county seat of local government in Howard County, Maryland, United States. It is part of the Baltimore–Washington Metropolitan Area. The population was 65,834 at the U.S. Decennial Census of 2010.
In 1766 James Hood used the "Maryland Mill Act of 1669" to condemn 20 acres (8.1 ha) for a mill site adjacent to his river-side 157 acres (64 ha) property. His grist mill was built on the banks of the Patapsco River where the Frederick road (later known as the old National Road, then United States Route 40/Maryland Route 144) crossed (later known as Ellicott's Upper Mills). His son Benjamin rebuilt the corn grinding mill after one of the frequent Patapsco floods in 1768. Benjamin Hood then sold the mill to Joseph Ellicott in 1774 for 1,700 pounds. In later years the B&O railroad ran through the property, with track laid over the graves of the Hood family.