An aerial view of the Penn Salt Company plant, likely at 6400 N.W. Front Avenue in Portland. A dock extends into the Willamette River, from the industrial facility (negative 1 of 3).

Photograph of 3 people at the Lewis and Clark Salt Works in Seaside, Oregon. They stand on the wall around the salt works and lean over the railing looking at large rocks. Handwriting on the back of the print reads, "Lewis & Clark salt camp 1804-5, Seaside. 1940." Stamp on the back for Photo-Art Commercial Studios.

Photograph of an illustration by artist Colista Dowling. Illustration depicts 5 kettles sitting on a fire on the beach. A furnace made of rock surrounds the kettles. The kettles are likely boiling ocean water to produce salt, a method used by Lewis and Clark in Seaside, Oregon in 1804-1805. The ocean is in the background. Colista Dowling's signature is on the lower left of the illustration. Stamp on the back indicates that the photograph of this illustration was taken by Al Ransford, Commercial Photographer.

Photograph of the Lewis and Clark Salt Works in Seaside, Oregon. The salt works are surrounded by a metal railing. A sign behind the railing is partially visible, showing the words, "Clark" and "Cairn." Handwriting on the back of the print reads, "Lewis & Clark Salt Cairn, Seaside, Ore." Stamp on the back for Arthur M. Prentiss, Commercial Photographer.

Photograph of the Lewis and Clark Salt Works in Seaside, Oregon. A sign in the middle of the salt works reads, "Site of Salt Cairn Used by Lewis and Clark 1805-6." A wooden fence made of tree branches stands around the perimeter of the monument. There are many rocks on the site. Stamp on lower right of print reads, "Gifford and Prentiss, Portland, Oregon. 1751."