Topic
- Dams 3
- Anniversaries 2
- Boats 2
- Bonneville Dam (Or. and Wash.) 2
- Cascade Locks (Or.) 2
- Cascade Range 2
- Columbia River Highway (Or.) 2
- Crowds 2
- Discovery and exploration 2
- Docks 2
- Explorers 2
- Maps 2
- Mountains 2
- Postcards 2
- Public works 2
- Railroad tracks 2
- Rapids 2
- Riparian areas 2
- Special events 2
- Transportation 2
