In 1935, during the depths of the Great Depression, frustration was growing in the small towns and the large ranches of the Great Plains. The wildly-scattered populations of northern Wyoming, southern Montana, and western South Dakota all felt ignored by their state governments. They were only getting the dregs of New Deal money, and the lack of infrastructure made them feel quite neglected. So they began planning to secede. Not from the United States, but from their states, to form a new, 49th state of their own named Absaroka.
The reason you haven't heard of Absaroka is because the process for carving a new state out of existing states was too difficult, but the campaign got that area, centered around Sheridan, Wyoming, a lot of attention from their respective state capitals. And that's why the idea resurfaced again in 1939 (when a Sheridan city commissioner appointed himself governor of Absaroka), and then again in 1977. Of course, Alaska became the 49th state, and Hawaii the 50th. Read about Absaroka, the state that never was, at Smithsonian.
(Image source: Wikipedia)
