Thornton, William, 1759–1828, American architect, b. Tortola, British Virgin Islands, He studied (1781–84) medicine at Edinburgh but received his medical degree (1784) at the Univ. of Aberdeen. In 1787 he emigrated to the United States and became a citizen in 1788. His plan for the Library Company in Philadelphia won a competition in 1789. Through Trumbull, the painter, he gained permission to submit a plan for the proposed Capitol at Washington in an official competition opened in 1792. Thornton's designs, submitted in 1793, were approved by President Washington, and their execution was entrusted to the supervision of E. S. Hallet and James Hoban. In 1794, however, Thornton himself, being appointed a commissioner of the District of Columbia, became supervisor and remained in charge until 1802. Despite important changes and additions, especially by Latrobe and Bullfinch, much of the design of the facade of the central portion of the Capitol is his. In Washington he also designed a number of residences, including the Tayloe house, known as the Octagon, later the headquarters of the American Institute of Architects. Thornton was the first to hold the post of clerk in charge of the Patent Office, and he served as commissioner of patents from 1802 until his death.