There were some archaeological digs made in the Seaside area in the 1970's. The carbon isotope dating of artifacts was under-written by the Smithsonian Institution in the 1970's. Items were found that were over 2000 years old, by which the lifestyle of the inhabitants could be determined. The Seaside Museum has part of that collection on display and a detailed report.
When Lewis and Clark arrived in 1805, they established their base camp in the form of a fort about 15 miles north of Seaside, not far from Youngs Bay. They found only about 250 Indians in the area, due to the dreaded disease Small Pox, which had been brought in by explorers and fur traders during earlier years. The Indians were the Clatsops, a peaceful tribe, occasionally meeting with the Chinooks on the north across the Columbia River, and the Tillamooks to the south.
From their Fort Clatsop base, Lewis and Clark made expeditions south and west to hunt, as well as to survey and make reports about the vegetation, wild life, and natives. Their travels took them to an area near the base of Tillamook Head and Seaside's Cove area, where there was a native village.
The Indians were living in "Long Houses", about 30 to 60 feet in length, made of cedar planks. A Long House floor was several feet below the ground level, with a fire pit in the center. Along the wall were shelves for sleeping and storage of food and belongings.
The Indians made their clothing of animal skins, cedar bark, bear grass, silk grass and flag. The garments of both sexes came no lower than the knees; allowing lower legs and feet to be bare summer and winter. During the rainy season, which was most of the time, they wore cloaks made of strips of bark bound together and coated with fish oil to make them waterproof but gave them a strong fish odor. They also coated their bodies with fish oil for warmth and protection.
The main staple of the Clatsop diet was fish but they also ate berries, roots, wild fruits, and some game. They hunted by digging a pit, covering it with branches and leaves, then sitting by to wait for the game to appear and fall in. They would dispatch the deer or elk with bows and arrows.
During the winter of 1805 and 1806, salt became scarce and was badly needed by the expedition for preserving meat and fish, and for the coming return trip. Three men from the group were assigned to the beach some distance north of Seaside's Cove area, to establish the "Salt Cairn", also known as the "Salt Works". They worked continuously from February 2 to February 20, 1806, boiling sea water from which they extracted four bushels of salt.
The site of that Salt Works in Seaside was determined by the Oregon Historical Society in 1900, after the location was pointed out to their committee by Jennie Meschelle. Her Clatsop parents had seen the white men boiling sea water, and had shown her the spot when she was a young girl (She was born about 1816). A piece of land at the site was donated to the Oregon Historical Society in 1910 from the estate of Charles M. Cartwright. A replica of the Salt Works was erected there by the Lions Club in 1955, using sketches from the Lewis and Clark Journals. The "Salt Works" is now a National Monument, and is located in Seaside, on Lewis and Clark Way between Beach Drive and the Prom.