Historically distributed throughout North America, most populations of elk (Cervus elaphus) were extirpated by the early 20th century. Merriam elk (C. e. merriami) were once native to Texas, USA, and became extinct after the beginning of the 20th century through excessive hunting and degradation of habitat. Since then, landowners and state agencies have reintroduced Rocky Mountain elk (C. e. nelsoni) into the Trans-Pecos region of Texas. We determined herd composition, density, and survival rate of elk in the Glass Mountains, Texas. Twenty-six total density surveys were conducted in September and October of 2009 and 2010. Survival rate was determined by monitoring radiocollared elk. Collectively, calf:adult female:adult male ratios were found to be at moderate levels of 49:100:39. Our density estimate of 0.39 elk/km2 (95% CI = 0.18–0.78 elk/km2) indicated the population could have stayed the same or possibly doubled in size since 1983 (0.21–0.22 elk/km2; Grace 1983). The elk density in the Glass Mountains was much higher than that estimated for the much larger Trans-Pecos region, which was 0.14 elk/km2 (95% CI = 0.03–0.33 elk/km2). We estimated annual survival of mature male elk at 97.1% and of female elk at 94.4%, both of which are comparable to other sustainable populations in arid lands. Elk are not subject to a regulated harvest in Texas. Forming a cooperative management program and improved estimates of population dynamics will result in better management recommendations to resource managers. © 2014 The Wildlife Society.