Federal agencies responsible for wildland fire management face increasing needs for personnel as fire seasons lengthen and fire size continues to grow, yet federal agencies have struggled to recruit and retain firefighting personnel. While many have speculated that long seasons, challenging working conditions, and low wages contribute to recruitment and retention challenges, there has been no empirical investigation of these claims. We assemble a unique dataset on the federally funded Interagency Hotshot Crews in the Western United States, which are comprised of highly qualified firefighters, from 2012 to 2018 to analyze the factors that affect firefighter retention. Using a Cox proportional hazard model, we find that a higher workload, a proxy for higher earnings, and cumulative experience over the course of an employee's career both have a significant positive impact on retention. The wage of alternative occupations had no significant effect on retention. Retention decreases over the study period.