Aubrey, Francois X., a noted scout and guide, was a French Canadian of whose early life and antecedents little is known. During the days of the Santa Fe trade he was a familiar figure along the old trail, and was the first man to take a loaded train from the Missouri river to Santa Fe in the winter season. In 1849 or 1850 he discovered a new route to Santa Fe by crossing the Arkansas river at the mouth of the Big Sandy, not far from Big Timbers, and following the divide between the Raton and Cimarron rivers. This route had an advantage over the old ones, as the longest distance between watering places was but 30 miles, while on the old trail via the Cimarron river the distance in some cases was 60 miles. For a wager of $5,000, Aubrey on one occasion rode from Santa Fe to Westport, Mo., a distance of 775 miles, in 5 days and 13 hours. He secured relays of horses from passing trains and won the wager, but was almost exhausted when he reached Westport and slept for twenty hours. Gen. Sherman mentions this ride in his Memoirs, and compliments the bravery and endurance of the scout. Aubrey met his death at Santa Fe in 1856 at the hands of Maj. R. C. Weightman, who afterward won distinction as an artillery officer in the Confederate army. Weightman and Aubrey met in a saloon and were in the act of taking a drink together, when the latter accused Weightman of publishing a lie on him, Weightman having formerly conducted a newspaper. Without replying to the charge, Weightman dashed his glass of liquor in the face of Aubrey, who immediately attempted to draw his revolver, but before he could do so his antagonist stabbed him to the heart.

Aubrey's name is sometimes given as "Felix X. Aubrey," and some writers spelled the last name "Aubry." In 1853 a steamboat built for the Missouri river trade was named the "Felix X. Aubrey" after this daring and adventurous character.