He was the first delegate from the Oregon Territory to the United States Congress and was instrumental in the passage of the Donation Land Claim Act.

[1] Then in 1848 he was elected to the Provisional Legislature from Tuality District where he served with fellow Hillsboro resident David Hill.

In the struggle for the control of Oregon lands, Thurston was an ally of Jason Lee against John McLoughlin, the chief of the Hudson's Bay Company at Fort Vancouver who Thurston, for shamefully political reasons, accused of helping thwart settlement in the territory.

Thurston and Lee made false statements about McLoughlin before the United States Supreme Court in an effort to publicly discredit him.

[6] While returning to Oregon via Panama, Thurston died of the effects of a tropical fever off Acapulco, Mexico while aboard the steamer California.

[7] According to a contemporary obituary: He died on the 9th [of April 1851] ... eight days from Panama ... His arduous labors at Washington had prepared his system for an attack of the malignant fever incident to the Isthmus, from the effects of which he had not recovered before experiencing a severe attack of diarrhea, which, together with an affection of the liver, under which he had sometime labored, terminated his earthly existence.