Built for Charles Hillyard III around 1798, this house was considered one of the grandest in Kent County. After Hillyard died in 1814, his son-in-law, Dr. Martin W. Bates, purchased it and lived here with his wife Mary and her three younger sisters. Daniel and Mary Cowgill bought the house in 1825, and the first known reference to the name "Woodburn" appeared in an 1845 letter by a Cowgill family member. Before Delaware had an official governor's residence, governors who did not live in Dover often stayed in rented quarters or with friends while the General Assembly was in session. In 1965, during Governor Charles L. Terry, Jr.'s term, the State of Delaware purchased Woodburn to serve as the official residence of the Governor of Delaware. First Lady Jessica Irby Terry oversaw the interior design during the renovations, choosing furnishings, textile treatments, and accessories inspired by the house's architecture and the elegance and classicism of the late 18th-century Georgian style. In 1966, she also began the tradition of opening Woodburn to the public. Although not all governors in the last forty years have used it as their primary residence, Woodburn has continually served for state functions including dinners, receptions, festivals, picnics, and public events.