The Northern Bobwhite (Colinus virginianus) has declined across its range. The primary cause of this decline is thought to be habitat loss and fragmentation. However, there is speculation that factors such as parasites may play a role. South Texas recently was designated a Legacy Landscape of National Significance for Northern Bobwhite Conservation and is a region with some of the highest bobwhite densities in the US. Limited studies on bobwhite parasites have been conducted in this crucial landscape. We documented helminth parasites infecting bobwhites in South Texas, identified those that are known to be pathogenic to quail, documented pathologic responses to infection, and evaluated infections related to host intrinsic and extrinsic factors. We examined 209 bobwhites and found nine species of helminths including two known to cause tissue damage in bobwhites: Tetrameres pattersoni and Oxyspirura petrowi. The cecal nematode Aulonocephalus pennula was numerically dominant and had the greatest prevalence, intensity, and abundance. Prevalence and abundance of A. pennula were significantly greater in adult than juvenile bobwhites, whereas host sex was not an important factor. Prevalence of A. pennula was significantly greater during the 2012–13 hunting season than the 2013–14 season. The abundance of A. pennula also was significantly greater in bobwhites with greater mass within each age cohort. This research provides insight regarding the factors that influence helminth infections in bobwhites from South Texas and highlights the importance of broad-scale surveys when assessing helminth infections across large regions.