South Dakota’s Oahe irrigation project (technically called the Oahe Unit) had its roots deep in the history of America and the Missouri River. The sequence of events leading to the intense and history-making public debate in the 1970s over the billion dollar (today’s dollars) Oahe irrigation project began with the earliest relationship of American citizens to the Missouri River. Issues related to the Oahe project and the Missouri River are inexorably linked, as the Oahe project was an integral aspect of plans to control and develop the Missouri River. This timeline delineates and discusses Missouri River and Oahe irrigation project events and provides a background showing how those events are related. It is notable that the political fight over the Oahe irrigation project had national implications, and resolution of that fight led to significant and lasting changes in federal water development strategies. Please note: This timeline divides the history discussed in this exhibit into four sections. To explore and examine the different time frames within each section, click on the section, below.