Henry Dearborn (February 23, 1751 – June 6, 1829) was an American physician, statesman and veteran of both the American Revolutionary War and the War of 1812. Born to Simon Dearborn and Sarah Marston in North Hampton, New Hampshire, he spent much of his youth in Epping, where he attended public schools. He studied medicine and opened a practice in Nottingham Square in 1772.

When fighting in the American Revolutionary War began, he organized and led a local militia troop of 60 men to Boston where he fought at Battle of Bunker Hill as a captain in Colonel John Stark’s First New Hampshire Regiment. He then volunteered to serve under Benedict Arnold during the ill-fated American expedition to Quebec. His journal is an important record for that campaign. He was captured on December 31, 1775, during the Battle of Quebec and detained for a year.

He was released on parole in May 1776, but he was not exchanged until March 1777. After fighting at Ticonderoga, Freeman's Farm and Saratoga, Dearborn joined George Washington's main army at Valley Forge as a lieutenant colonel where he spent the winter of 1777–1778. He fought at the Battle of Monmouth in 1778, and in 1779, he accompanied Major General John Sullivan on the Sullivan Expedition against the Iroquois in upstate New York. Dearborn joined Washington’s staff in 1781 as deputy quartermaster general with the rank of colonel, and was present when Cornwallis surrendered after the Battle of Yorktown.

In June 1783, he received his discharge from the army and settled in Gardiner, Maine, then part of Massachusetts, where he worked as a U.S. marshal for the District of Maine. He represented this district as a Democratic-Republican in the Third and Fourth Congresses (1793-1797). In 1801, President Thomas Jefferson appointed him Secretary of War, a post he held for eight years until March 7, 1809. During his tenure, he helped plan the removal of Indians beyond the Mississippi River.

He was appointed collector of the port of Boston by President James Madison in 1809, a position he held until January 27, 1812, when he was appointed senior major general in the United States Army in command of the northeast sector from the Niagara River to the New England coast. While Dearborn prepared plans for simultaneous assaults on Montreal, Kingston, Fort Niagara, and Detroit, the execution was imperfect. He did not move quickly enough to provide sufficient troops to defend Detroit and as a result, William Hull surrendered the city to Isaac Brock. Although Dearborn had minor successes at the capture of York (now Toronto) on April 27, 1813, and at the capture of Fort George on May 27, 1813, his command was, for the most part, ineffective. He was recalled from the frontier on July 6, 1813, and reassigned to an administrative command in New York City. He was later appointed president of the court martial which tried and condemned General William Hull, even though Dearborn's own negligence contributed to Hull's defeat. Dearborn was honorably discharged from the army on June 15, 1815.

President James Madison nominated Dearborn for reappointment as Secretary of War, but the Senate rejected the nomination. He was later appointed Minister Plenipotentiary to Portugal by President James Monroe and served from May 7, 1822, to June 30, 1824, when, by his own request, he was recalled.

He retired to his home in Roxbury, Massachusetts, where he died 5 years later. He is interred in Forest Hills Cemetery, in Jamaica Plains outside of Boston. Dearborn married three times: to Mary Bartlett in 1771, to Dorcas (Osgood) Marble in 1780, and to Sarah Bowdoin, widow of James Bowdoin, in 1813.Henry Alexander Scammell Dearborn was his son by his second wife.