In 201,1 the Alaska Department of Fish and Game used dual frequency identification sonar (DIDSON) to estimate sockeye salmon (Oncorhynchus nerka) escapements into the Kenai, Kasilof, and Yentna rivers of Upper Cook Inlet, Alaska. Bendix Corporation side-looking sonar equipment enumerated sockeye salmon escapement into the Crescent River. Only Kenai, Kasilof, and Crescent rivers escapement estimates were used inseason for management purposes. Yentna River escapement ranges were estimated postseason for sockeye, pink (O. gorbuscha), chum (O. keta), and coho (O. kisutch) salmon by adjusting DIDSON estimates using six sets of fish wheel selectivity indices obtained from the literature. Approximate sockeye salmon escapement estimates were 1,600,000 into the Kenai River, 246,000 into the Kasilof River, 62,000–140,000 into the Yentna River, and 82,000 into the Crescent River. The predominant age classes for sockeye salmon in the Kenai River were 1.3 (38.9%) and 2.3 (45.6%); Kasilof River – 1.3 (31.5%), 2.3 (25.6%), 2.2 (25.2%), and 1.2 (13.7%); Yentna River – 1.3 (55.9%), 0.3 (18.1%) and 1.2 (11.3%); and Crescent River – 1.3 (51.4%), and 2.3 (33.9%). Length and sex ratio information were collected for sockeye salmon in each river.