These tribes exist today, in their modern forms, and struggle with state and local governments over natural resource policies, especially water management. The image on the right (taken by patrick mccully) shows members of the Yurok tribe protesting building dams on the Klamath river.
The Jefferson region was among the last places in the continental US to be explored by Europeans and Americans. Not until the 1820's was this region formally explored, and settlement didn't begin until gold was discovered in present day Yreka in 1851. During this time, the gold rush was already well under way, though focused further south in california. The discovery of gold in the Jefferson area caused thousands of gold prospectors in central california to migrate north. Most gold prospectors left the area after the gold rush ended, leaving behind them ghost towns, some of which still remain today.
The Jefferson region is rich with natural resources such as timber and fish, and these became the primary means of income for the communities that began populating the area after the gold rush ended.
However, the distribution of transportation infrastructure funding was not even, and the Jefferson region received very little funding for roads and bridges. This caused discontent among the people who lived in Jefferson. Transportation infrastructure was essential to the areas economic prosperity - without it, transporting the raw materials extracted from the area was impossible. This became the root cause of the proposal of a state of Jefferson. Jeffersonians felt as though they were being double crossed by their respective state governments because the rural to urban flow of money and resources was, in their view, unfair. They felt angry that their taxes did not fund their own public infrastructure, and were instead being used to further develop state capitols Sacramento and Salem.
American involvement in WWII starting in 1941 ended the growing campaign to establish Jefferson as its own state.
The Jefferson flag - the two 'X's represent being double crossed by state governments. (http://www.jeffersonstate.com/jeffersonflag.html)