Southwestern pond turtles (Actinemys pallida) have declined throughout Orange County over the past century. Aliso Creek is thought to have one of the largest remaining southwestern pond turtle populations in Orange County. Over 3 years, we investigated a population of southwestern pond turtles to assess the demographics, including population size, sex ratio, and recruitment. We estimate that over 100 southwestern pond turtles reside within the investigated portion of Aliso Creek. This study occurred after of a large arundo removal project in the creek. Further investigation is needed to understand the effects of arundo removal on pond turtle population recovery.