Wildland fire regimes vary with human population density, topography, and climate. The significance of these factors is often difficult to understand and identify at short temporal and small spatial scales. Dendrochronological fire histories from Arkansas, Indiana, Missouri, Ontario, and Tennessee offer a quantitative means of examining the dynamics of anthropogenic fire regimes. We examine temporal and spatial patterns in the frequency of fire that are forced by human ignitions, topographic roughness, fuels, and cli mate. An analysis of temporal variability in fire intervals over the last three centuries reveals phases in fire regimes when fire frequency is limited by (1) anthropogenic ignition; (2) surface fuel production; (3) fuel-fragmetation; and (4) cultural values. Topographic roughness and human population density are the most important factors influencing the spatial variability in fire intervals in areas with diverse topography. Topographic roughness mitigates the propagation and subsequently the frequency of fire during periods of low human population density, but is much less important when there are abundant human ignitions. The surrounding topographic roughness, human occupation, and floodplain fuels influence riparian fire regimes. Humans are the keystone species in most fire regimes and are hypothesized to be an underlying causal factor influencing all components of modern fire regimes. Changes in ignitions, fuels, rural development, and climate all lead back to increases in human population density at the local, regional, and global scales. © 2004 by the Ecological Society of America. Abstract reproduced by permission.