This article draws on recent interventions related to everyday states, state-natures, and political ecologies of the state, as well as Timothy Mitchell’s concept of “state as effect,” to detail and analyze ongoing changes in southeastern Turkey associated with the large-scale Southeastern Anatolia Project (Guneydoğu Anadolu Projesi, or GAP). Using interviews and survey data, the essay details changing narrations and understandings of the Turkish state among villagers of Turkey’s southeast, revealing the importance of social and historical processes, as well as differentiated biophysical conditions and changing access to water resources for these imaginaries. The case study explains both ways that state-society relations evolve as well as ways that the state is expressed as distinct from society, in part in relation to the varied and important changes associated with the ongoing damming and diversion of the Tigris and Euphrates rivers. Apart from contributions to understandings of the state and state-society dynamics in the long-contested southeastern Anatolia border region, the work also advances state theory. Specifically, the article builds on arguments related to the importance of political ecology and socionatural approaches, detailing key analytics related to these approaches that provide important insights for state theory—spatiotemporalities, inequality and differentiated access to resources, scalar dynamics, and materialities of nature. Harris argues that these analytics have considerable potential to advance state theory and state-nature approaches, particularly to draw out ways that the state emerges as seemingly distinct from society—the “state effect.” Scale, Harris argues, may be particularly useful toward this end and to expose other key processes of importance for states and stateness as they relate to development and nature.