Ancon Rock is a reef about 0.5 miles (0.8 km) off Point Gustavus on the eastern shore and at the entrance to Glacier Bay, in Glacier Bay National Park and Preserve, about 55 miles (89 km) west of Juneau and 8.5 miles (12 km) southwest of Gustavus, Alaska. The reef is named after the sidewheel steamship Ancon that ran aground here in 1886. The reef is a submerged extension of a glacial moraine that formed Point Gustavus during the Little Ice Age of the Neoglacial period. A moraine is an accumulation of unconsolidated rock that was carried along by a glacier or ice sheet and deposited. A moraine may consist of partly rounded rock particles ranging in size from very large boulders to gravel, sand, and very fine clay. Terminal moraines are formed by ice shoving as the glacier advances and they typically are aligned perpendicular to the ice stream and mark the maximum extent of glacier advance. Lateral moraines are generally aligned parallel and are formed at the sides of an ice stream. The Neoglacial period occurred between 5500 and 200 years ago. In the centuries before the maximum glacial advance, the glacier filling present-day Glacier Bay had formed a stationary front at the head of Bartlett Cove and built an outwash plain southward to the mouth of Glacier Bay. The glacier started advancing around 1700, overflowing the central trench of Glacier Bay, and spilling onto adjacent lands. In 1794, Lieutenant Joseph Whidbey of the Vancouver Expedition mapped the Glacier Bay icefield terminus when it had already begun retreating from the terminal moraine but still extended well out into Icy Strait. The glacial advance built a lateral moraine that aligns diagonally into the center of Glacier Bay forming Point Gustavus, although the present-day feature most likely has an earlier origin. The landscape of Point Gustavus forms a rolling surface comprised of well-drained mineral soils that allowed trees to quickly grow after deglaciation. The area is now densely forested with first-generation stands of Sitka spruce and some western hemlock. The terminal moraine is mostly submerged in Icy Strait but merges with the lateral moraine at Point Gustavus. Post-glacial rebound is causing a gradual uplifting of the submerged bottom which has elevated the submerged moraine to form reefs, and today, vessels are advised to stay well offshore when rounding Point Gustavus. Ancon Rock is a notorious navigational hazard that uncovers 1 foot (0.3 m) at low tide about 0.4 miles (0.6 km) south-southwest of Point Gustavus, and another rock uncovers 3 feet (1 m) at low tide about 0.2 miles (0.3 km) northwest of Ancon Rock.

In 1867, the Alaska Purchase transferred the territory from Russia to the U.S., and a mild post-Civil War rush of miners, fishermen and prospective settlers arrived to seek opportunities in the newly acquired territory. By 1873, efforts to establish a mu­nicipal government at Sitka had collapsed, and many optimistic pioneers returned to the ‘lower 48’. In 1877, occupa­tion units of the U.S. Army, after ten years of idleness, gladly abandoned the territory. In 1879, a band of Tlingits threatened Sitka, and the British man-of-war HMS Osprey had to be called in to save the lawless town. During the early 1880s, Alaska’s appeal to fortune seekers enjoyed a resurgence when gold was discovered at Juneau. At about the same time, salmon canneries and herring salteries were proliferating. The number of vessels traveling the Inside Passage multiplied accordingly. Companies like the Pacific Coast Steamship were finding profit in transporting gold, fish, lumber, and mining equipment, but they also sought paying passengers to fill empty berths. In 1879, John Muir first visited Alaska and the articles he wrote described the attractions of an Inside Pas­sage vacation. A few years later Captain James C. Car­roll delighted the passengers aboard his steamer SS Idaho with the fairyland sights of Glacier Bay. He demonstrated that under the right conditions an ocean-going vessel could successfully maneu­ver in waters crowded with icebergs. Of all the captains engaged in the Southeast Alaska maritime trade, Carroll was undoubtedly the most notorious. His reputation for dodging liquor smuggling indictments matched his re­nown for skirting reefs and shoals. In 1883, Eliza Scidmore from Iowa wanted to see more of the world and purchased a ticket to Alaska on Idaho. She wrote newspaper and magazine articles about her travels and in 1885 published the first Alaska travel guide. While in Glacier Bay, Scidmore described meeting Tlingit families hunting in Glacier Bay for the summer, interactions with pioneers like Dick Willoughby, and the efforts Captain Carroll took to get Idaho to the face of a tidewater glacier. These publications and others influenced the opening of Alaska to western tourism.

SS Ancon was launched in 1867 as a double-ended ferry for service in Panama for the Pacific Mail Steamship Company. In 1872, the hull was rebuilt, a larger engine of 400 horsepower was installed, and the capacity was significantly increased for transporting passengers and cargo. In this configuration, Ancon sailed between San Francisco and San Diego from 1875 to 1887, and in 1878 Ancon also made periodic trips between San Francisco and Portland. Cruising to Alaska became popular in the 1880s, so the Pacific Coast Steamship Company used Ancon for summer excursion cruises sailing the Inside Passage between Puget Sound and Alaska. At 9:57 pm on September 13, 1886, Ancon was under the command of Captain Carroll and cruising past Point Gustavus in Icy Strait, heading into Glacier Bay. Most of the 14 passengers were asleep in their staterooms when the ship made the turn into Glacier Bay and grounded hard on an uncharted rock. Three hours later the tide had risen sufficiently for Ancon to float free, but water in the hold had extinguished the boiler fires and both the pumps and engines were disabled. The sails were raised, and Carroll beached the ship on a sandy shore in Bartlett Cove. There was no radio in 1886, so Carroll sent the ship’s launch to Sitka on the morning of September 14 to seek help. While the initial repairs were made on the beach, the passengers played cards, and the local Tlingit Natives stopped by to see the unusual sight. The USS Pinta arrived on September 19 from Sitka, bringing carpenters and planking for repairs. On September 26, Idaho arrived, and the passengers were transferred. No other ship carried news of the wreck to the world until Idaho reached Victoria, British Columbia with Ancon’s passengers on October 8. The U.S. Coast and Geodetic Survey was immediately sent to chart the rock, which they named ‘Ancon Rock’. Ancon was repaired and returned to service, and three years later, on August 28, 1889, after departing from Loring, Alaska with cases of processed salmon, Ancon ran onto a submerged and uncharted reef in the harbor and sank. Read more here and here. Explore more of Ancon Rock here: