The Henry’s Fork Foundation, working with the University of Idaho, will utilize otolith microchemistry to gain a better understanding of trout life history and movement patterns in the Lower Henry’s Fork from Ashton Dam to north Fork of the Teton River to better understand spawning, rearing and migration patterns. By collecting this information in this part of the lower Henry’s Fork, this project’s potential management implications include flow management, diversion screening, hydropower project licensing, angling opportunities, and land use planning. The twenty-two miles of mainstem Henry’s Fork in this area is under intense and steadily increasing pressure from water users, land development, one of the most rapidly developing cities in the country (Rexburg) and the angling public, yet little is known about the trout populations in this area. This project will assist in identifying the location and originating source of the trout that inhabit this stretch of river.