These Elliott’s were found in the 1850 Oregon Census
Hope this helps.
Elliott, O. Oregon Territory 1850 Clatsop
Elliott, Nimrod 1850 Washington
Elliott, William Clackamas
Elliott, William H. Lewis

Land records for the Oregon territorial period of 1844 to 1857 were kept with the territorial recorder. These records are indexed and are in the Oregon State Archives. Early settlers who were in Oregon by 1855 may have received grants called Donation Land Claims

Oregon Cemetery Survey (Salem, Oreg.: Oregon Department of Transportation, 1978). This volume records the location of every known cemetery in Oregon by utilizing modern highway maps of each county to show the location of each cemetery. Published and microfilmed cemetery records are at the Oregon State Library, various public libraries, and genealogical societies throughout the state.

Article--Elliot Wagon Train 1853 Oregon Trail, Haney Historical Highlights Vol., 16 No 7 Oct 1992
Publisher: Harney County Historical Society
Publisher Address: PO Box 388 : Burns, OR 97720
Persi Code: ORHC

Article--Dave Elliot, Confederate Recalled, Deschutes Country Yesteryear
Publisher: Deschutes County Historical Society
Publisher Address: PO Box 5252 : Bend, OR 97708
Persi Code: ORDC

1890 Census Records
1890 LANSING CHARLES H. Union County OR 001 Hilgard Precinct
1890 LANSING HENRY W. Union County OR 002 Pine Valley OR
1854 LANSING PATRICK Jackson County OR