The 1855 reservation was large, encompassing most of the traditional nimíipuu territory.

The leaders who signed it understood it as a guarantee of permanence: in exchange for acknowledging American sovereignty and agreeing not to harm settlers, the nimíipuu would be secure on their land.

The guarantee lasted eight years.

The 1863 treaty, which reduced the reservation by ninety percent, was negotiated in response to the gold discovery and the attendant settlement pressure.

It was a drastically different document from the 1855 treaty, and it was presented to the assembled nimíipuu leaders not as a renegotiation of the fundamental terms of their relationship with the United States but as a necessary adjustment to circumstances.