Intra-state regional differences are a central topic in the study of European and Eurasian politics. In Ukraine, regional differences have proven to be powerful predictors of mass attitudes and political behavior. But what does the "regional factor" in Ukrainian politics represent? Is it simply the result of compositional effects, or are the regional differences more than just a sum of other demographic factors correlated with geographic divisions? When analyzing regional divisions as an explanatory variable, what are the implications of employing different regional frameworks? In this article, we demonstrate how geographic divisions in the country hold up even when others factors-such as ethnicity and language use-are controlled for. As part of this inquiry, we compare the results of three competing regional frameworks for Ukraine: one with two regions, one with four regions and one with eight regions. While the eight-region framework is uncommon in studies of Ukraine, the decision to examine eight regions is supported by historical, economic and demographic arguments, as well as by the results of the statistical analyses presented in this article. Scholars who have focused on fewer regions in Ukraine may have underestimated the effects of regional differences and missed interesting stories about intra-state variation in Ukrainian attitudes and voting behavior. The results of this study carry important implications not only for the study of Ukraine but also for those interested in intra-state regional divisions across Europe and Eurasia.It is taken as a truism by most scholars of post-Communist Europe that in Ukraine, more than in most countries, geography matters. The existence of powerful intrastate regional divisions in mass attitudes and political behavior (e.g. voting) in Ukraine has been a theme of numerous studies (Birch, 2000;Kubicek, 2000;Craumer and Clem, 1999;Barrington, 1997;Holdar, 1995). But what does it mean that there are strong regional differences in attitudes and behavior? Are the regional differences simply "compositional effects" (capturing other things that scholars claim are important in Ukraine such as language and ethnicity), or are they capturing underlying divisions that can be adequately disentangled from ethnicity and language and exert an independent effect? This question is a focus of our article. But we argue that it is not enough to demonstrate that regional divisions exist even when language and ethnicity are controlled for, as others have shown in