Blackstone Glacier flows north for 7 miles (11 km), terminating at tidewater at the head of Blackstone Bay, about 87 miles (140 km) west-southwest of Valdez and 8 miles (13 km) south of Whittier, Alaska. The glacier originates at an elevation of approximately 5,000 feet (1,500 m) in the Kenai Mountains. The glacier and bay were named after Charles A. Blackstone, a gold prospector from Seattle. The local name was first reported in 1899 by Walter C. Mendenhall of the U.S. Geological Survey. Blackstone Bay is a fjord on the Kenai Peninsula in western Prince William Sound. It trends northeast for 13 miles (21 km) to the entrance of Passage Canal, about 10 miles (16 km) east-northeast of Whittier. The bedrock exposed by the retreating glacier consists of partially metamorphosed sedimentary rocks from the Valdez Group, part of the Southern Margin composite terrane. This terrane extends more than 1,056 miles (1,700 km) along Alaska’s southern coast. The Valdez Group primarily comprises complexly deformed graywacke, siltstone, and shale. These rocks formed during the Late Cretaceous from deposits by turbidity currents in a deep oceanic trench along a subduction zone. Over time, they were accreted to the margin of North America.

In 1896, Charles A. Blackstone left Seattle on a steamship with 250 other men, hoping to find gold in Alaska. During the journey north, he teamed up with Charles Botcher and J.W. Malinque, planning to prospect near the Hope and Sunrise mining camps in Turnagain Arm. Upon landing at Seldovia in Kachemak Bay, near the mouth of Cook Inlet, they learned that traveling to Turnagain Arm would be difficult due to strong tidal currents and shallow water. It took them most of the summer to reach the Sunrise camp, and by then the prospecting season was largely over. In March 1897, out of funds and supplies, the dispirited group decided to return to Seattle. They planned to walk from Sunrise over Portage Pass to Passage Canal on Prince William Sound, where they would board a ship. The route was arduous but clearly marked and well-known to other prospectors. However, the group encountered severe winter conditions in the mountain pass. They likely became disoriented in a snowstorm and missed a critical turn. A search party later discovered the remains of Charles Blackstone high in the mountains, far from the route, on what is now called Blackstone Glacier. He had left a note describing their ordeal, which led to the deaths of Botcher and Malinque from the cold on April 1, 1897. Blackstone died sometime after April 4, when the note was written. The bodies of Botcher and Malinque were never found.

In 1909, Ulysses S. Grant and Daniel F. Higgins visited the fjord where Blackstone Glacier was then a massive ice field surrounding the head of Blackstone Bay, discharging at least ten separate ice streams. Since that time, the ice field has thinned and separated into individual glaciers. Only Blackstone and Beloit Glaciers, both located at the head of the bay, now reach tidewater. Blackstone Glacier is 7 miles (11 km) long, covering an area of 7,900 acres (3,200 ha). It has an accumulation area of 7,166 acres (2,900 ha) and an ablation area of 494 acres (200 ha). The glacier’s terminus is 1,640 feet (500 m) wide. There is evidence that Blackstone Glacier once extended to the north end of Willard Island, approximately 5.5 miles (9 km) northeast of its current terminus. A prominent submarine terminal moraine, partially exposed at most tidal levels, connects Willard Island, located in the middle of Blackstone Bay, to the eastern shore. Grant and Higgins suggest that this moraine predates the early 18th century. Read more here and here. Explore more of Blackstone Glacier and Blackstone Bay here: