<p>Reconstructing Canada’s cropland over the past millennium reveals human-land relationships and informs strategies for climate change mitigation. Canada’s population and per capita cropland area are estimated for 1000–1840 by analyzing and revising historical documents. These estimates are then multiplied and combined with census data to obtain the cropland area of Canada for 1000–2015. Then, using a sophisticated land suitability map for cultivation, a cropland area allocation model is constructed, and the spatial pattern of cropland in Canada for the past millennium is mapped using the model and the maximum extent of cropland in different periods. The results indicated that the cropland area increased from 0.078 million ha in 1000 to 38.690 million ha in 2015, with slow growth before 1900 and rapid growth thereafter. The spatial distribution of cropland in Canada expands gradually from the Great Lakes-St. Lawrence Lowlands to the western prairie area, with land use intensity increasing and exhibiting spatial heterogeneity over the past millennium. This high-resolution, spatially explicit reconstruction aligns more closely with Canada’s agricultural history than several noteworthy global datasets. Archaeological data are needed to enhance subsequent land use estimation and mapping for Canada.</p>