The fire history of the northern Great Plains has been largely reconstructed from the historical record. To clarify this history, segments of 1-m cores from four lakes in North and South Dakota and northeastern Montana were examined for charcoal fragments. The cores spanned a time interval of 172 to 380 yr. Samples integrating 5-10 yr of deposition were taken from 2-cm sections along each core and sieved. Charcoal concentrations ranged from 6-14,799 fragments/gram of sediment, and mean charcoal abundance was negatively correlated with longitude. Results suggest periods of increased fire from A.D. 1700-1740 and A.D. 1850-1900. These peaks were broadly synchronous across the region and ranged in duration from 20-40 yr. Postsettlement patterns of charcoal deposition were highly variable but generally much lower than presettlement intervals.