Four pollen zones are present in a 360-cm core of sediment from Rice Lake, Becker County. The zones indicate a vegetation succession from mid-postglacial oak savanna to deciduous forest to pine-hardwood forest to an uppermost ragweed zone representing postsettlement forest disturbance. Seeds of wild rice occur in the upper meter of the core with abundant wild rice type pollen. The initial increase of wild rice type pollen is radiocarbon dated at 2450 ± 100 years ago. The ragweed pollen rise that dates land settlement about 75 years ago is radiocarbon dated at 590 ± 95 years ago. The difference is attributed to contamination by dead carbon, and when this error is subtracted from the older date, the corrected age for the spread of wild rice across the lake is 1935 ± 100 radiocarbon years ago.An extensive stand of wild rice at this lake predates by 1000 years prehistoric cultures known to have used wild rice in Minnesota.The spread of wild rice is probably due to either climatic change and associated changes in water quality or to shallowing of the lake by sedimentation, or both factors.