Thornton, Matthew (1714?–1803), an American patriot and a signer of the Declaration of Independence. Thornton was born in Ireland and was brought to America as a child. He became a doctor and settled in New Hampshire about 1740. Soon active in state politics, he became a leading figure in the patriot cause. Thornton was elected to the Continental Congress after the Declaration of Independence had been drafted in 1776, and was thus one of the last delegates to sign the document. He served in the Congress for about a year and then returned to New Hampshire, where he was a supreme court judge until 1782.