Marys Slough is a side channel about 5 miles (8 km) long at the mouth of the Unalakleet River formed by a barrier spit on Norton Sound that creates an extensive tidal wetland, about 46 miles (74 km) northeast of Saint Michael and 1.1 miles (1.8 km) south-southeast of Unalakleet, Alaska. The local name is in honor of an Iñupiaq woman named Sinrock Mary, famed for her part as an interpreter for Captain Michael A. Healy, commander of the U.S. Revenue Cutter Bear during the first reindeer purchase for Alaska from Siberia. The Unalakleet River comprises several tributaries that all have headwaters in the Kaltag Mountains. The mainstem is roughly aligned with the Kaltag Fault and starts at an elevation of about 2300 feet (700 m) and flows generally southwest for 65 miles (105 km) to Norton Sound at the village of Unalakleet. The combined watershed, which includes the Unalakleet River, South River, Chiroskey River, Old Woman River, and North Fork, drains an area of 1,332,179 acres (539,114 ha). The Kaltag Fault is a major strike-slip fault from the Cretaceous with right lateral offset of the bedrock that has been traced for 275 miles (443 km) across west-central Alaska. The principal bedrock underlying the watershed consists of nonmarine sedimentary rocks such as shale and sandstone.

The community of Unalakleet, meaning ‘from the southern side’, is located at the south end of the Unalakleet-Kaltag Portage, an important winter travel route and the shortest connection between Norton Sound and the Yukon River. Unalakleet has long been a major trade center between the Athabascans who live in the interior of Alaska and the Iñupiat who live on the coast. Archaeologists have dated house remnants on the beach ridge at Unalakleet to over 2000 years ago. Athabaskan people inhabiting the upper river were considered ‘professional’ traders, with a monopoly on the trade across the portage divide. Because of the active trade route, Unalakleet has a history of being a crossroads for many different cultures and a center of commerce for Norton Sound. In the 1830s, the Russian-American Company built a trading post at Unalakleet. In the late 1800s, while Healy commanded the USRC Bear, he observed that Chukchi people in Siberia had domesticated reindeer, and used them for food, travel, and clothing. He also witnessed the decline in the walrus, seal and whale populations from commercial hunting, and the resulting loss of food and subsequent starvation of indigenous peoples. To compensate for this, Healy worked with Reverend Sheldon Jackson, a Presbyterian missionary and political leader in the territory, to introduce reindeer to Alaska as a source of food. In 1898, Sámi reindeer herders from Lapland were brought to Unalakleet to establish a domestic herd and teach husbandry practices.

Sinrock Mary was a daughter, named originally Changunak, of an Iñupiaq woman and a Russian trader who became one of the richest women in Alaska due to her work in the reindeer industry. She spent her childhood in the late 1800s in Saint Michael, a small island on Norton Sound about 50 miles (80 km) southwest of Unalakleet. At that time, the island was a trading post and saw the arrival of many foreign ships with Yankee whalers, Russian traders, rum runners, merchants, and missionaries. Her exposure to these people allowed her to learn English, Russian, as well as other Alaskan Native languages. One reindeer herd imported from Siberia was landed at the mouth of Sinuk River, or Sinrock, about 26 miles (42 km) northwest of Nome, and Mary and her husband Charley Antisarlook grew the herd to 500 animals. Mary sold reindeer meat to the U.S. Army at Fort Davis, a post established to keep order in Nome following a nearby gold discovery. In 1900, Charley succumbed to a measles epidemic, and Mary moved the herd to the mouth of the Unalakleet River. A documentary on her life was released in 2000, see a preview here. In 2009, Mary was inaugurated into the Alaska Women’s Hall of Fame. Read more here and here. Explore more of Marys Slough and Unalakleet River here: