Three new sediment cores from the Chukchi Sea preserve a record of local paleoenvironment, sedimentation, and flooding of the Chukchi Shelf (∼−50 m) by glacial-eustatic sea-level rise. Radiocarbon dates on foraminifera provide the first marine evidence that the sea invaded Hope Valley (southern Chukchi Sea, −53 m) as early as 12 ka. The lack of significant sediment accumulation since ca. 7 ka in Hope Valley, southeastern Chukchi Shelf, is consistent with decreased sediment supply and fluvial discharge to the shelf as deglaciation of Alaska concluded. Abundant benthic foraminifera from a site west of Barrow Canyon indicate that surface waters were more productive 4–6 ka, and this productivity varied on centennial time scales. An offshore companion to this core contains a 20 m record of the Holocene. These results show that carefully selected core sites from the western Arctic Ocean can have a temporal resolution equal to the best cores from other regions, and that these sites can be exploited for high-resolution studies of the paleoenvironment.