Animal movements and habitat selection within the home range, or microhabitat selection, can provide insights into habitat requirements, such as foraging and area requirements. The King Rail (Rallus elegans) is a wetland bird of high conservation concern in the United States, but little is known about its movements, habitats, or demography. King Rails (n = 34) were captured during the 2010–2011 breeding seasons in the coastal marshes of southwest Louisiana and southeast Texas. Radio telemetry and direct habitat surveys of King Rail locations were conducted to estimate home ranges and microhabitat selection. Within home ranges, King Rails selected for greater plant species richness and comparatively greater coverage of Phragmites australis, Typha spp., and Schoenoplectus robustus. King Rails were found closer to open water compared to random locations placed 50 m from King Rail locations. Home ranges (n = 22) varied from 0.8–32.8 ha and differed greatly among sites. Home range size did not vary by year or sex; however, increased open water, with a maximum of 29% observed in the study, was correlated with smaller home ranges. Breeding season cumulative survivorship was 89% ± 22% in 2010 and 61% ± 43% in 2011, which coincided with a drought. With an equal search effort, King Rail chicks and juveniles observed in May-June decreased from 110 in 2010 to only 16 in the drier year of 2011. The findings show King Rail used marsh with ≤ 29% open water and had smaller home ranges when open water was more abundant.