The Skykomish inhabited at least 8 permanent villages with a pre-contact population believed to number in the thousands.

After the signing of the treaty, the Skykomish were removed to the Tulalip Reservation, where they gradually intermixed and assimilated with their neighboring and closely-related Snohomish and Snoqualmie peoples.

By 1871, the Skykomish had begun to virtually disappear from the historical record, generally being classified as Snohomish or Snoqualmie.

The 1855 Treaty of Point Elliott lists the Skykomish as a signatory tribe, separate from the Snohomish and Snoqualmie.

[4] As the Skykomish became more and more close to the Snohomish and Snoqualmie in post-treaty times, it became more difficult to distinguish between them and their neighbors, causing a debate among anthropologists and historians.

The Snoqualmie Tribe was hoping to gain compensation for the land ceded to the US government on behalf of the Skykomish.

The Skykomish were known for their skills in poling river canoes, while the Index people were known for their aptitude in quickly traversing the difficult terrain of the Cascade mountains.

However, during the Puget Sound War of 1855-56, the Skykomish remained neutral, following the lead of the prominent pro-American Snoqualmie leader Patkanim.

Seven Skykomish representatives signed the treaty: Smehmaihu, Lugsken, Weaipah, Pehnus, Twooiaskut, Hehmahl, and Stehshail (William).

The Skykomish began to disappear from official records in the 1870s due to their growing intermarriage with the Snohomish and the Snoqualmie peoples on the reservation.

[15] At Juanita Bay in 1933, the Skykomish were represented by Chief Black Thunder, also known as Mr. Bagley in a reenactment of the signing of the 1855 treaty.

[10] Other than the Snoqualmie and Snohomish, the Skykomish had close relations and frequent contact with several other peoples, namely the Stillaguamish and the Nxaʔamxcín-speaking Wenatchi across the mountains.

Around August, Skykomish activity in the Puget Sound would die down as they would travel back home to the Sultan Basin to go elk hunting and focus on the salmon runs.

The cold winter months, when not engaging in religious ceremonies, were often spent building canoes, houses, and all other crafts.

As the winter drew to a close, many Skykomish would fish for steelhead in the Pilchuck River (Lushootseed: dxʷkʷiƛ̕əb)[1] and begin preparing for the summer activities.

This consisted of plant life (sand rush, salmonberries, strawberries, blackberries, blackcaps, salalberries, huckleberries, blueberries, blue elderberries, hazelnuts) and animal (deer, elk, mountain goat, salmon, clams, and cockles).

Most fish caught were smoked or dried, but some were eaten fresh or traded for other goods, especially during the colonial period.

The Pilchuck Basin was shared between the Snoqualmie and Snohomish and was a popular hunting area for deer and bear, as well as elk.

Goat wool in particular was a highly valuable trade good, prized by Puget Sound peoples with limited access to the mountains.

Mountain berries were gathered and sold fresh to settlers at lower elevation, or made into dried cakes for storage.

Ethnologist Colin Tweddell believed the Skykomish spoke a subdialect of Northern Lushootseed, along with the Snohomish.

However, in the same year, the Indian Claims Commission concluded that the Skykomish spoke Southern Lushootseed, as do the Snoqualmie.