steep-walled, flat-bottomed basin with a depth of approximately 200 ft.[1] described as a hanging valley that formed during more extensive Pleistocene glaciation.

Shoup Bay is an Ice Age remnant but its name is far more recent: as late as the early 1900s, the nearby glacier was referred to as "Canyon Creek Glacier"; it wasn't until 1899 that Captain W. R. Abercrombie had the local name "Shoup" reported to him, referring to the glacier,[4] and it wasn't until 1905 that the U.S. Geological Survey (USGS) noted the waterway as Shoup Bay.

Shoup Bay State Marine Park is located five miles southwest of the Port of Valdez.

Due to a cold microclimate, timber is sparse in the Shoup Glacier valley,[1] with the uplands consisting mostly of new growth forest of alder and spruce.

Waterfowl flock in abundance here, from the black-legged kittiwake rookery in the lagoon to bald eagles and arctic terns.