Small mammal populations and species habitat selection were examined for one year (4 seasons) in six different tallgrass prairies in northwestern Arkansas, two in the Arkansas River Valley, and four in the Ozark Plateaus. Populations varied between sites and seasons. Hispid cotton rats ( Sigmodon hispidus) were the most abundant and occurred at all sites. Some eastern harvest mice (Reithrodotomys humulis) and individuals tentatively identified as meadow voles (Microtus pennsylvanicus) were caught. Multivariate analysis of means for habitat selection showed that white-footed mice occurred close to the prairie-forest edges, selected the least amount of grass cover, and lowest grass height of all species. Results also showed the three species, hispid cotton rats, fulvous harvest mice, and deer mice all occurred in the taller grasses than the random plots. Climate seemed to affect Lake Fayetteville populations and a general trend between after-treatment age at sites and abundance of small mammals was discovered.