Those early relationships were generally positive, and the nimíipuu maintained them carefully through the first half of the nineteenth century.

For decades, they navigated an expanding American presence with diplomacy and restraint.

The treaty of 1855, negotiated by Governor Isaac Stevens of Washington Territory, recognized a large nimíipuu territory and attempted to define the boundaries within which the people and the United States would coexist.

Many nimíipuu leaders signed it, including those from the bands in the Wallowa Valley of northeastern Oregon and along the Salmon River and its tributaries.

The reservation it established was large — millions of acres — and included most of the traditional homeland.