Hale v. Port of Portland, 783 P. 2d 506 - Or: Supreme Court 1989 provides:
The Oregon Territory adopted the English common law in two acts.
Statehood did not change the law.

Article XVIII, section 7, of the Oregon Constitution, adopted in 1859, provides:
"All laws in force in the Territory of Oregon when this constitution takes effect, and consistent therewith, shall continue in force until altered or repealed."

Oregon recognized common law name change in Ouellette v. Ouellette 420 P. 2d 631, 245 Or. 138 - Or: Supreme Court, 1966:
The court recognized that at common law a person could change his name at will without legal proceedings and that such proceedings were merely an aid to the establishment of a name change.