The purpose of this article is to help education practitioners and researchers understand that research about rural education is complicated not only by issues of defining "rural," but also by the often dramatic ways that rural schools differ from each other. We briefly address issues in defining rural and describe rural classification systems that two federal agencies use to identify rural places. Our main emphasis, though, is on showing the differences among rural schools and districts as identified under the standard U.S. Department of Education (US DOE) definition of rural. Students in rural schools nearest to towns and cities have distinctly different demographics from those in more distant and remote settings. Researchers in rural education should consider explicitly whether or not to use the standard US DOE definition of rural schools and districts, a modified version, or an alternative. Whichever definition is used, researchers should consider how the demographics of their selected group of schools or districts compare in race/ethnicity, family income, enrollment trends, and other characteristics to all schools or to other categorizations of rural schools.