List of steamboats on the Columbia River Early Oregon Steam Navigation Company boats Table 4: Early 
 O.S.N. Monopoly 
 boats

| Name_ | Type_ | Year_Built | Where_Built | Initial_Owners |
|---|---|---|---|---|
| Mountain Buck | side | 1857 | Portland | Ruckle & Olmstead |
| Hassaloe | stern | 1858 | Cascades, Washington | Bradford Bros. |
| Carrie Ladd | stern | 1858 | Oregon City | Jacob Kamm & John C. Ainsworth |
| Julia(Barclay) | stern | 1858 | Port Blakely | Oregon Steam Navigation Co. |
| Wasco | stern | 1858 | Port Blakeley | Oregon Steam Navigation Co. |