Dennis Hart Mahan (Mă-hăn) [məˈhæn] was a noted American military theorist, civil engineer and professor at the United States Military Academy at West Point from 1824–1871. He was the father of American naval historian and theorist Rear Admiral Alfred Thayer Mahan.

Alfred Thayer Mahan was a United States naval officer and historian, whom John Keegan called "the most important American strategist of the nineteenth century." His book The Influence of Sea Power Upon History, 1660–1783 (1890) won immediate recognition, especially in Europe, and with its successor, The Influence of Sea Power Upon the French Revolution and Empire, 1793–1812 (1892), made him world-famous.