Work carried out in 1990 at Kuzitrin Lake in the Seward Peninsula interior of western Alaska resulted in the discovery of early Classic Denbigh Flint complex remains dating to 5,500 calibrated years BP, and persisting to 4,000 calibrated years BP. This assemblage includes various burin types, burin spalls and serrated endblades. Comparison with early Denbigh remains from Iyatayet, Cape Denbigh, reveals that the same technology is represented in the Iyatayet and Kuzitrin Denbigh assemblages. Comparison with Onion Portage Denbigh reveals important differences between Kuzitrin and Iyatayet with respect to the Onion Portage Proto-Denbigh assemblage, dating to 3,999-4,084 calibrated years BP. Proto-Denbigh was previously postulated as an antecedent of Classic Denbigh. The early Classic Denbigh represented at Iyatayet and Kuzitrin Lake can be regarded as an initial manifestation in the Bering Strait area of a Siberian cultural diffusion into the North American Arctic. The subsequent spread of the culture to northern and southern Alaska and as Independence I assemblages in the Canadian Arctic occurred later, sometime around 4,500 years ago. By 4,200 years ago, later Denbigh-related remains are represented in increasingly large numbers of sites in many areas of Alaska and in the eastern North American Arctic.