Denis Julien (born c. 1772) was an American fur trapper of French-Canadian Huguenot origin best known for his activity in the southwestern United States in the 1830s and 1840s, at a time when he was one of the few people of European descent in the area. He is principally remembered for his habit of leaving carved inscriptions on rock faces in Utah and Colorado during his travels. At least eight such markings have been positively attributed to him, four of which are listed on the National Register of Historic Places.