Denis Julien (b. circa 1772) was an American fur trapper of French Huguenot origin who was active in the southwestern United States in the 1830s and 1840s, one of the few Europeans in the area at the time. He is principally known for his habit of leaving carved inscriptions in rock faces in Utah and Colorado on his travels, with at least eight such locations attributed to him, four of which are listed on the National Register of Historic Places.
Julien apparently lived in St. Louis in the 1790s. A child was born in 1793 to Julien and his native American wife Catherine in 1793, and three children were christened and one was buried between 1798 and 1809. Julien was mentioned in an 1808 letter by then-governor Meriwether Lewis to Secretary of War Henry Dearborn as an "old and rispected [sic] trader among the Ioways." Julien and his brother were in the military in northern Louisiana in 1809. Denis witnessed the 1815 Iowa Treaty and traded on the upper Missouri River in 1816 and 1817. In this time he was connected to the Chouteau and Robidoux families of St. Louis.
In 1827 Julien made his first trip to the far West with Francisco Robidoux. They passed through Taos and went to "the land of the Utes," in the general area of Southern Utah and Colorado. From that time Julien is known only by his series of rock inscriptions. He was the first to leave a dateable mark in the land in the area. He left marks in 1831, 1836 and 1844, apparently traveling up and down the Colorado and Green rivers in a boat, apparently assisted by sail, since one of his inscriptions depicts a boat with a mast.
- Denis Julien Inscription (Moffat County, Colorado), Dinosaur National Monument
- Denis Julien Inscription (Grand County, Utah), Canyonlands National Park
- Denis Julien Inscription (San Juan County, Utah), Canyonlands National Park
- Julien Inscription Panel, Arches National Park
All listed on the National Register of Historic Places.
- Pierson, Lloyd (November 1990). "National Register of Historic Places Registration Form: Julien, Denis, Inscription". National Park Service. Retrieved 3 November 2011.
- Julien Inscription Panel at Canyonlands National Park