The Nisga'a, who lived around the Nass River, called the head of Portland Canal "Skam-A-Kounst," meaning safe place, probably because it served them as a retreat from the harassment of the Haidas on the coast.[1] They traveled in the area seasonally to pick berries.

The area around the Portland Canal was explored in 1896 by Captain D.D. Gaillard of the U.S. Army Corps of Engineers.[1]

In 1898, gold and silver lodes were discovered in the region, mainly on the Canadian side, in the upper Salmon River basin. The Stewart brothers, for whom the British Columbia town was named, arrived in 1902.

Hyder was established in 1907 as "Portland City", after the canal.[2] In 1914, when the US Post Office Department told residents that there were many U.S. communities named Portland, it was renamed Hyder, after Frederick Hyder, a Canadian mining engineer who envisioned a bright future for the area. Hyder was the only practical point of access to the silver mines in Canada; the community became the port, supply point, and post office for miners by 1917. Hyder's boom years were the 1920s, when the Riverside Mine on the U.S. side extracted gold, silver, copper, lead, zinc, and tungsten. The mine operated from 1924 to 1950.

In 1928, the Hyder business district was consumed by fire.[1] By 1956 all significant mining had ceased, except for the Granduc Mine on the Canadian side, which operated until 1984 and 2010 to present.[3] Westmin Resources Ltd operated a gold and silver mine on the Canadian side in Premier, British Columbia, but is not currently active.[4]