Circa 1880: Jargon with the Coeur d’Alenes
But I’ve re-found it.
Here we have legitimate information corroborating our impression that Chinook Jargon was current in northeastern Washington (beyond the Columbia River), and northern Idaho, from middle-to-late frontier times.
It’s from the Autobiography of John Creig Lawrence (1861-1912).
1858 horse-slaughter camp on the Spokane River (image credit: Wikipedia)
On the old CHINOOK listserv in 2005 I commented:
This is interesting because it fills in gaps in our knowledge of Chinuk
Wawa use in the Inland Northwest, especially in Northern
Mr. Lawrence was born in 1861 in Ohio and lived in
Illinois. He moved west by railroad train in 1876 to San Francisco,
catching a steamer to Portland, and at the age of 18 [circa 1879] taught at a school in
Colfax, Washington where “the noted missionary”, “Father Eells” (the one
who spoke Chinuk Wawa?) was in charge. Colfax is at the southern edge of
Snchitsu’umsh (Coeur d’Alene Salish) territory, and the following takes
place there. — Dave R.
Now here’s the text that I quoted:
“During the summer many Coeur d’Alene Indians passed. I learned to talk
the Chinook jargon so I could carry on a conversation fairly well. Only
about a score of years had passed since the  Steptoe battle. I always led
the conversation to that event and talked with scores of Indians who had
taken part. While they were voluble in describing the fight with Steptoe,
an Indian victory, they became instantly silent when asked about Wright.
It was only a little while after the Steptoe battle that Col. Wright
came. He rounded up all the Indian ponies a few miles above Spokane and
shot them, leaving the Indians afoot. He then called in a number of
Chiefs who had taken part in the Steptoe battle and hanged them on a creek
afterward known as Hangman Creek.”