I stumbled upon Map Bureau via BlogMapper. The default map seemed so right it took me a minute to think "Hey, why are they using the mouth of the Columbia River?" Turns out these high tech, interactive mapping folks, are in Astoria, Oregon. They've got a lovely set of maps including:

Lewis & Clark in Oregon and Washington

Dredging Deposit History

Dams and Salmon

Lewis & Clark in the Columbia-Pacific

and my favorite...

The Flower Stands of the Clatsop Plains.