Obligation (Harwood, Maryland)  Obligation is a historic home at Harwood, Anne Arundel County, Maryland, United States. It was begun in 1743 and later enlarged in 1827, to two and one-half stories. The house was built for Thomas Stockett III, and was enlarged to its present configuration during the ownership of his grandson, Joseph Noble Stockett (1779-1858). Thomas Noble Stockett (1747-1802) was the son of Thomas III, and became a prominent citizen and served as surgeon for the Maryland Line during the American Revolutionary War. Obligation was listed on the National Register of Historic Places in 1969.