Despite recent interest in the North American fire record, paleoecological evidence for the deliberate burning of grassland by hunter–gatherers has not previously been sought. Through the analysis of grass phytoliths preserved in a sequence of buried soil horizons in the Lauder Sandhills, southwestern Manitoba, Canada, this article reconstructs a local grassland fire record for the past 5,000 years. I propose that an apparent peak in fire frequency shortly after 2,500 14C years b.p. corresponds to the deliberate burning of prairie by Sonota–Besant (Plains Woodland) hunter–gatherers, rather than climatic “forcing.” This practice, which is clearly documented in the historic record, may have functioned as a means of making bison–herd movements more predictable and may have enabled higher human carrying capacities in the Plains Woodland period. This hypothesis is meant to stimulate multidisciplinary discussion on a significant, but neglected, topic.