We report new stable isotope and radiocarbon data on a small set of human remains representing seven individuals from three archaeological sites in northeastern California, CA-MOD-205 (Franklin Creek site; n = 2), CA-LAS-989 (Bare Cave; n=4), and an unrecorded site near Honey Lake (n =1). Results reveal several points of interest for dietary reconstructions, mobility patterns, and the antiquity of Northern Side-Notched points. First, one of the samples from LAS-989 produced a calibrated radiocarbon date in excess of 7,800 cal B.P., one of the oldest human bones dated in northern California. This sample is associated stratigraphically with Northern Side-Notched projectile points, demonstrating the antiquity of this point style. The other samples consistently dated to the Late Holocene (2,200 to 1,200 cal B.P.). Second, dietary isotopes indicate that all individuals had a mixed diet, including C3 plants and large game, as expected, but they also consumed significant quantities of fish, including varying quantities of a 13C-enriched food, likely salmon or Tahoe sucker. Third, serial samples of dentin collagen from one woman near Honey Lake indicate that she was weaned between 3.1 and 3.7 years of age, and had periodic and fluctuating access to this 13C-enriched food resource during later childhood and teenage years, with a periodicity around 3ñ4 years. We attribute this to either a residentially mobile settlement system with exploitation of a key and periodically-abundant resource, or to a structured fiesta system involving regular visits to a location on a major river. Finally, sulfur and oxygen isotopes suggest that most individuals had been living in northeastern California (i.e., were local) for a number of years prior to their deaths.