The first and only millennial tree-ring chronology (AD 978–1941) in northwest Alaska was developed in the 1940s by archaeologist and dendrochronology pioneer J. L. Giddings. Constructed from living trees and archaeological samples from the Kobuk River valley, Giddings’s sequence established the chronology of the “Arctic Woodland Culture.” As Alaskan archaeology shifted to the search for the Earliest Peoples, radiocarbon dating offered broader applicability in wood-lacking sites, supplanting dendrochronology. Since 2010, researchers have returned to excavate coastal Birnirk and Thule houses in northwest Alaska, realizing the greater chronometric precision of tree-rings and their paleoclimatic applications, to supplement Giddings’s database with architectural wood that refines the chronological and climate framework within AD 750–1200, a pivotal period in the development of Inuit culture. We present the results of conventional dendrochronology (ring-width) of 250 archaeological spruces (*Picea sp.) from the Kobuk River and northern Alaska. We cross-dated sites using floating chronologies, comparing our sample sequences (n = 70) with Giddings’s, extending its weakly defined earlier centuries (pre-AD 1400) by increasing sample size five-fold. The augmented sequence offers extended spatiotemporal resolution for climate and archaeological studies in northwestern Alaska, focusing on the Medieval Climate Anomaly and transition to Little Ice Age.