Sentinel Island is located along the eastern shore of Lynn Canal in the center of Favorite Channel near the northern entrance, about 51 miles (82 km) south-southeast of Haines and 25 miles (40 km) northwest of Juneau, Alaska. The island was probably named in 1869 by Commander R.W. Meade of the U.S. Navy. Favorite Channel is the preferred route for vessels north and southbound in Lynn Canal, a heavily used marine transportation corridor from near the city of Juneau north to the cities of Haines and Skagway.

The discovery of rich gold deposits in the upper Yukon River area at the close of the 19th century prompted a massive rise in the number of ships navigating Lynn Canal. This was the main route to Skagway for most of the stampeders heading to the Klondike goldfields. In 1898, at the peak of the gold rush, navigating the Inside Passage was very challenging because of strong currents, fog, rain, and numerous uncharted rocks and reefs. But this route was still preferable as a safer route for ships than the open ocean route through the eastern Gulf of Alaska. In the late 1890s, watercraft of every description converged upon the Pacific Northwest ports to sail north and over 300 accidents in Inside Passage waters were reported in 1898. This prompted the construction of lighthouses in Alaska and the first to be built were the lights on Sentinel Island and the Five Finger Light Station south of Juneau.

The Sentinel Island Lighthouse was activated on March 1, 1902, but navigating Lynn Canal was still treacherous. Early in the morning of August 5, 1910, the Canadian Pacific SS Princess May was southbound from Skagway carrying 80 passengers and a crew of 68 when she ran aground on a reef just off the northern end of Sentinel Island. The close proximity of Sentinel Island allowed a safe place to evacuate the passengers and crew, as well as land the gold shipment and the mail for safekeeping. Later the passengers and crew were picked up by SS Princess Ena and other rescue ships and taken to Juneau. On October 24, 1918, a particularly vicious storm hit Southeast Alaska. The fully loaded SS Princess Sophia departed Skagway at 10:10 p.m and at 2:10 a.m. ran onto Vanderbilt Reef at cruising speed. A fleet of rescue vessels from Juneau rushed to the site but had to retreat to the shelter of Sentinel Island Light Station. The following morning, the rescue boats returned to Vanderbilt Reef and saw only a twenty-foot section of the Princess Sophia‘s mast visible above the water. None of the 353 passengers and crew members survived. On 25 July 1933, SS Northwestern ran aground off Sentinel Island and subsequently was beached on the Eagle River Sand Spit. In 1935, the original wooden lighthouse on Sentinel Island was replaced with a concrete tower built in an Art Deco style. The light station was automated in 1966. Read more here and here. Explore more of Sentinel Island here: