Oldmans Bay spans about 3 miles (4.8 km) across and is situated on the southwestern coast of Kalgin Island in Cook Inlet, about 55 miles (89 km) northwest of Homer and 30 miles (48 km) west-southwest of Kenai, Alaska. The local name was first reported by the U.S. Geological Survey in 1958. Kalgin Island, located on the west side of Lower Cook Inlet, is approximately 13 miles (21 km) long. The island’s name, derived from the Tanaina language, was first documented in 1840 by Russian scientist Ilya G. Wosnesenski. In 1802, the name “Isla del Peligro,” meaning “danger island,” appeared on charts published by Spanish explorer Dionisio A. Galiano.

The Kalgin Island Critical Habitat Area is adjacent to Oldmans Bay and comprises a flat expanse of wetlands surrounding Swamp Creek on the southeast shore of Kalgin Island. Swamp Creek flows northeast for about 3 miles (4.8 km) to Cook Inlet. This critical habitat provides essential spring and fall resting and feeding grounds for swans, geese, ducks, and shorebirds. It serves as an important alternative habitat for a portion of the thousands of waterfowl that also use the nearby Redoubt Bay wetlands each year.

Oldmans Bay is mostly an exposed mudflat at low tide, supporting a moderately rich variety of invertebrates such as clams and worms. Large boulders scattered across the mudflat are glacial erratics, providing a stable habitat for rockweed, periwinkles, whelks, and barnacles. Despite the harsh conditions of Lower Cook Inlet, these plants and animals withstand major disturbances from wave action, currents, and seasonal ice scour. Read more here and here. Explore more of Oldmans Bay and Kalgin Island here: