RESUMEN
This study offers a first-of-its-kind investigation into the spatial and temporal transformation of agricultural land use and expansion in crops and livestock at national scale during the middle and latter half of the 19th century. We introduce an innovative methodological framework that combines historical data with advanced spatial analysis to trace and map the evolution of frontiers of agricultural land use changes, illustrating Denmark's agricultural evolution towards the modern era. Our research uncovers critical shifts in cropland, grazing land, and livestock density offering unprecedented insights into the mechanisms driving agricultural expansion and intensification. The mechanisms driving this expansion and their potential impact on contemporary agroecological challenges linked to land use intensification are explored. Our results point to a significant broadening and shifting of land use frontiers offering a historical perspective on agricultural land use. This sets the stage for promoting the analysis of drivers of change and gaining insights into how landscape development could be steered into an environmentally and societally more desirable and sustainable direction tackling present-day agroecological challenges.