George Frederick Ruxton (24 July 1821 – 29 August 1848) was a British explorer and travel writer. He was a lieutenant in the British Army, received a medal for gallantry from Queen Isabella II of Spain, was a hunter and explorer and published papers and books about his travels to Africa, Canada, Mexico and the United States. He observed the westward expansion of the United States in the 1840s during the period when the country's government was pursuing its policy of manifest destiny. He was the first author to write "extensively" of the mountain men of the Rocky Mountains.