Port Althorp is the site of a historical salmon cannery and a military facility situated on the north coast of Chichagof Island, in a deep embayment that extends southeast for 5 miles (8 km) from the George Islands between the Inian Peninsula to the east and the Althorp Peninsula to the west, about 155 miles (250 km) southeast of Yakutat and 29 miles (47 km) southwest of Gustavus, Alaska. The bay was named in 1794 by Captain George Vancouver, after George J. Spencer, 2nd Earl Spencer, who was Viscount Althorp from 1765 to 1783, and First Lord of the Admiralty from 1794 to 1801. Chichagof Island is in the Alexander Archipelago of Southeast Alaska, directly north of Baranof Island and separated by Peril Strait. It is bounded by Chatham Strait to the east, Icy Strait to the northeast, Cross Sound to the northwest, and the Gulf of Alaska to the west. Southeast Alaska was involved in oblique subduction of the Pacific plate beneath the North American plate during the Middle Mesozoic period. In the Early Cenozoic, this subduction boundary evolved into a dominantly transform boundary. On Chichagof Island, this tectonic history is represented by a complicated pattern of thrust faults, oblique-slip faults, and strike-slip faults. The major faults separated the geology of the island into three tectonostratigraphic terranes named the Alexander terrane, Wrangellia, and the Chugach terrane. Port Althorp is surrounded mostly by the Chugach terrane which is a thick accretionary complex dominated by Paleocene trench fill turbidites, most likely derived from a volcano-plutonic complex, that lithified into greywacke. The bedrock at Port Althorp is a diorite that intruded the Chugach terrane as a pluton during the Late Jurassic or Early Cretaceous. This bedrock is overlain by Quaternary alluvial and glacial deposits that created the relatively level ground along the shore.

Chichagof Island was one of the last of the large islands in Southeast Alaska to be settled by Euro-Americans, and little is known of the history of the area before 1800. The Huna Tlingit known also as Sheet’ka Kwaan have traditionally occupied this area of Southeast Alaska. Oral history and scientific findings corroborate that the ancestors of the Huna Tlingit occupied Glacier Bay long before the last glacier advance. This was their home and known as S’e Shuyee or ‘edge of the glacial silt’. Beginning around 1700, the long-stationary glacier in present-day Glacier Bay surged forward and overran their settlements. The clans survived by dispersing throughout the Icy Strait, Excursion Inlet, and northern Chichagof Island areas. Eventually, they settled in the village of Xunniyaa meaning ‘shelter from the north wind’, today known as Hoonah. Chichagof Island has been known historically by various names. Early Russian maps show it as Sitka Island, Chicagos Island, and Tchitchagoff Island. Captain James Cook sailed along the coast in 1778, and later Cape Cross was named by mapmakers from a cross on his chart that indicated his position on May 3, 1778. Cross Sound certainly was named because of its proximity to Cape Cross. Vancouver in 1794, with the ships HMS Discovery and HMS Chatham, entered Cross Sound on returning from Prince William Sound. He spent 3 weeks mapping Port Althorp while three small boats were dispatched under the leadership of Lieutenant Joseph Whidbey to explore Icy Strait and Lynn Canal. The island was first known to the Russians as Yakobi or Jakobi, but in 1805, the island was named by Yuri Lysianskyi after Admiral Vasili Y. Chichagov. In 1905, a rich gold-bearing vein, later known as the Chichagof vein, was discovered and the mining town of Chichagof was founded soon after. The salmon industry expanded rapidly just before and especially during World War I when the federal government purchased canned salmon to feed soldiers. In 1918, the Deep Sea Salmon Company established a new cannery at Port Althorp using equipment from its former cannery in Knik Arm. The facility was one of 16 new canneries that started operations that year in Alaska. Port Althorp was chosen for its proximity to Cross Sound where migrating salmon could be readily intercepted. Rising salmon prices fueled an expansion of the cannery and during the 1920s, and the 1930s it was one of the largest facilities in Southeast Alaska. On August 4, 1940, a fire burned through most of the buildings, and the complex was not rebuilt.

In 1930, the only significant military presence in Alaska consisted of a garrison of 400 U.S. Army troops at Fort William Seward near Haines. As Japan gained ambition to become an imperial power, American military planners recognized the potential for warfare in the Pacific. War Plan Orange was created with a perimeter that extended from the Panama Canal Zone to the south, the Territory of Hawaii to the west, and the Territory of Alaska to the north. Naval aircraft and surface vessels would deploy from bases at the vertices of this triangle in hopes of intercepting enemy forces well before they could threaten the contiguous United States. In the latter half of the 1930s, squadrons of Navy P2Y-3 flying boats and their support vessels, converted World War I destroyers, were deployed to bays and harbors around Southeast Alaska for a few months at a time. They would fly round trip patrols to Attu Island at the end of the Aleutians once a week. In December 1938, the Naval planning board endorsed the construction of three full Naval Air Stations in Alaska at Sitka, Kodiak, and Dutch Harbor. A construction consortium from Washington called Seims Drake Puget Sound began work in late August 1939. In 1940, the contract was increased to include six smaller dispersed bases for each naval air station. Dispersed bases under Naval Air Station Sitka initially included Annette Island, Port Armstrong, Port Althorp, Yakutat, Cordova, and Ketchikan. The Navy turned the Cordova and Ketchikan bases over to the U.S. Coast Guard in 1942. Most of the bases appropriated pre-existing civilian structures. In 1942, the remains of the cannery at Port Althorp were requisitioned by the U.S. Navy for use as a Navy Auxiliary Air Station. The usable buildings consisted of a dock with dock warehouse, separate bunkhouses for white and oriental employees, a mess hall and galley, cold storage, a watchman’s house, a building adjoining the scow ways, and fuel tanks for diesel oil and fuel oil. By 1943, 110 military personnel and four aircraft were based at Port Althorp to maintain daylight patrols of convoys going to the military base at Excursion Inlet. The Navy decommissioned the facility on June 1, 1944. Read more here and here. Explore more of Port Althorp here: