These primary cities, together with adjoining unincorporated communities and several small towns, comprise a Humboldt Bay Area with a total population of nearly 80,000 people.

[8] In addition, the bay and its complex system of marshes and grasses support hundreds of thousands of migrating and local shore birds.

Several marinas also located in Greater Eureka have the capacity to serve hundreds of small to mid-size boats and pleasure craft.

Despite being the only protected harbor along nearly 500 miles (800 km) of coastline, the bay's location was undiscovered or at least unreliably charted for centuries after the first arrival of European explorers to the Pacific Coast.

Contributing to the bay's isolation were features of the coastal mountain range, which extends from the ocean approximately 150 miles (240 km) inland, and the common marine layer (fog) in addition to frequent clouds or rain.

[6] Humboldt Bay began to form when a river valley drowned about 10,000 to 15,000 years ago during a period of rapid sea level rise.

The old reservation, roughly 20 acres, was originally purchased by a local church group to relocate homeless Wiyot in the early 1900s.

[13] Although relatively small, Wiyot territory encompassed miles of old growth redwood forests, sandy dunes, wetlands and open prairies.

Every year, around the month of February, the Wiyot people would gather for their World Renewal Ceremony on Indian Island, which lasted 7 to 10 days.

[15] In the early morning hours of February 26, 1860, local settlers from the nearby town of Eureka descended onto Indian Island armed with firearms, clubs, knives, and hatchets.

[15] Through grassroots fundraising, and with the help of the community and individual donors, the Wiyot Tribe was able to purchase back 1.5 acres of the historic village site of Tuluwat on Indian Island in 2000, and in 2004, the Eureka City Council made history as they unanimously approved a resolution to return approximately 45 acres, comprising the northeastern tip of Indian Island, to the Wiyot Tribe.

Because of the density of the redwood forests, and because Gregg stopped frequently to measure latitude and the size of the trees, the expedition averaged only two miles per day.

After considerable initial difficulty with waves breaking heavily over shifting sands of the bar crossing,[21] the ships entered the bay in 1850.

The members of the Laura Virginia company named the bay after Alexander von Humboldt, a noted German naturalist of that time.

The litigation spanned 13 years and involved extensive historical research, including evidence of original deeds and lawsuits dating back to before the establishment of the city.

These documents, along with copies of many historical maps as well as a series of contemporary aerial photographs and archaeological findings commissioned for the case, are included in Cal Poly Humboldt's Eureka Waterfront Litigation Collection.

[23] The donated dolos was slated for demolition due to sale of this property by the City of Eureka in 2022, but it was relocated to Madaket Plaza through a community effort.

This reduced tidal connectivity along the eastern edge of the bay, which resulted in deterioration of large areas of marsh habitat.

The bay supports more than 100 species of marine and estuarine fish, including green sturgeon, coho and Chinook salmon, steelhead and coastal cutthroat trout, which spawn and rear in its watershed, covering an area of 223 square miles (580 km2).

[30] The federally endangered tidewater goby is found in the bay, along with more common three-spined stickleback, shiner perch and Pacific staghorn sculpin.

[6] Leopard sharks have been reported inside the bay, which also provides habitat for young bat rays, feeding on clams, crabs, shrimps, worms, sea cucumbers, brittle stars, various gastropods and isopods.

Dangerous sand bars and shifting currents have caused many shipwrecks at the entrance to Humboldt Bay, particularly during the late nineteenth century.

[34] The Humboldt Bay National Wildlife Refuge was established in 1971 to conserve and protect a diverse habitat full of mammals, migratory birds, fish, amphibians, and plants.

Factors such as freshwater habitat degradation, timber harvest activities, and diversion of water for agricultural and municipal purposes influenced coho salmon populations.

[38] Humboldt Bay NWR acquired the land in 1988 and deemed Salmon Creek in need of restoration to improve estuarine habitats.

[38] Phase 1 of restoration began in 2006 and aimed to increase tidal connectivity, construct new tide gates, and to reconnect several off channel ponds to the stream.

Situated on Humboldt Bay National Wildlife Refuge, the Lanphere Dunes are home to many unique plant and animal species.

Along with European Beachgrass, Yellow Bush Lupine (Lupinus arboreus), another invasive species, was introduced from an adjacent property nearby.

Dunes are considered to be a hostile ecosystem because of environmental conditions such as low soil fertility, summer drought, ocean spray, harsh winds, and intense albedo.

[40] Removal of European Beachgrass requires multiple visits over the course of several years due to the plants' tenacious rhizome.