The Sadie River flows generally west-northwest for 6 miles (10 km) to the head of Sadie Cove on the southern shore of Kachemak Bay, about 14.5 miles (23 km) south-southeast of Homer and 13 miles (20 km) east-northeast of Seldovia, Alaska. The river originates on the western flank of the Kenai Mountains at an elevation of about 3,200 feet (975 m). Sadie Cove was named in 1880 by William H. Dall of the U.S. Coast and Geodetic Survey in honor of Sarah “Sadie” Eldred, the wife of Marcus Baker. The Sadie River watershed contains rocks from the McHugh Complex, characterized by massive conglomerate and graywacke blocks, which can be several kilometers thick. The graywacke originated from turbidites formed during the Early Jurassic to Early Cretaceous period—201 to 145 million years ago—based on radiolarian chert fragments. These turbidite deposits were lithified, metamorphosed, and eventually uplifted, becoming part of the Chugach terrane. This terrane is an accretionary composite that dominates the southern coast of Alaska.

Marcus Baker was an American mathematician, astronomer, explorer, journalist, and newspaper editor. In 1872, he was hired by William H. Dall as the astronomer for an expedition to Alaska aboard the survey cutter Yukon. During this mission, he collected navigational, topographical, and hydrographical data. At the time, Alaska was regarded as an unexplored wilderness of ice and fog. Baker continued to accompany Dall to Alaska annually until 1888, when he co-founded the National Geographic Society. He also became one of the first editors of National Geographic Magazine. He was one of the 15 original signers of the articles of incorporation for the National Geographic Society in 1888. Baker was renowned for his work in geology and cartography. He dedicated much of his time to completing and publishing the first comprehensive “Dictionary of Alaskan Geo­graphic Names,” which was released in 1902. He also contributed significantly to discussions on the Northwest Boundary Surveys of the United States conducted from 1857 to 1861. Mount Marcus Baker, located in the Chugach Range of southern Alaska, is named in his honor.

The Sadie River estuary, located at the head of Sadie Cove, was surveyed in the 1970s as part of a biological reconnaissance of lower Cook Inlet. The most common intertidal soft-substrate invertebrates included gaper clams, Dungeness crabs, true seastars, and sunflower stars. Primary producers in this ecosystem were eelgrass, sea lettuce and sugar kelp. Adjacent to the estuary is Sadie Peak, with a summit elevation of 4,320 feet (1,317 m), dominating the southern skyline of Kachemak Bay in Kachemak Bay State Park. The park, covering 400,000 acres (161,874 ha) in and around Kachemak Bay, is the first state park in the Alaska State Parks system to be designated by legislation. Adjacent to it is the Kachemak Bay State Wilderness Park, the only wilderness park in Alaska to receive a legislative designation. Most areas of the park are inaccessible by road, so visitors typically arrive by plane or boat from Homer. Read more here and here. Explore more of Sadie River and Kachemak Bay here: