Larch species are the dominant elements of coniferous forests in eastern Siberia, representing a large reservoir of carbon in their biomass and soil. The present study evaluated the effect of topography on the abundance of larch forest in entire eastern Siberia. Correlation coefficients (CCs) between the overstory leaf area index (LAI) and topographic properties of each larch-dominated plot were calculated for every 0.5-degree grid. To explain the forest's geographic heterogeneity, principal component analysis was conducted to summarize all environmental variables including the CCs. The results suggested that larch forests avoid areas with drought risk in grids with positive principal component 1 (PC1), and avoid areas with inundation/over-wetting risks in grids with negative PC1. The larch LAI averaged over eastern Siberia was slightly higher during wetter years indicating a drought-mediated regulation of larch abundance; this trend was more apparent for grids with larger PC1 and PC2. Regions with higher PC1 were likely characterized by higher elevation, higher slope, shallower soil, higher surface-permafrost coverage, lower annual-precipitation, and lower GDD5, all of which accelerate aridity. These results suggest that topographic heterogeneity controls the abundance of larch forest under both drought and over-wetting stresses.