The Kachemak tradition was established by ca. 3000 B.P. in Kachemak Bay. Probably somewhat later a variant termed Riverine Kachemak, with a population adapted to salmon and terrestrial resources, appeared on the northern Kenai Peninsula. The Kachemak tradition people seem to have abandoned Kachemak Bay by ca. 1400 B.P. Seven of 12 available Kachemak tradition dates predate 1400 B.P. even at two sigma. Scattered younger dates are thus suspect outliers. The end of Riverine Kachemak tradition has been placed at ca. 1000 B.P., at which time the population was supposedly replaced by in-migrating groups ancestral to the Dena'ina Athapaskans. Close examination of the numerous available radiocarbon dates shows that most Riverine Kachemak dates cluster in the early centuries of the First Millennium A.D. and most Dena'ina dates substantially postdate 1000 A.D. Probably the Riverine Kachemak and Dena'ina peoples never met on the Kenai River. However, the correspondence in date ranges between Kachemak Bay and Riverine Kachemak is striking, suggesting their fates were linked. Both traditions collapsed by 1400-1500 B.P. The causes are probably multiple but do not include cultural replacement.