An interactive digital hydro-climatologic atlas of Colombia, HidroSIG, has been developed with distributed maps and time series of monthly and long-term average hydro-climatological variables, as part of a more comprehensive geographical information system (GIS) and database. Maps were developed so as to capture the spatial variability of the diverse geophysical fields resulting from major geographic, topographic and climatic controls. HidroSIG contains modules that perform diverse hydrological and geomorphological estimations including: (i) extraction of geomorphological parameters of drainage channel networks and river basins from Digital Elevation Maps (DEM), (ii) estimation of long-term and monthly water balances and other hydro-climatic variables in river basins, (iii) estimation of extreme flows (floods and low flows) of different return periods along the river network of Colombia by combining long-term water balance with scaling methods, (iv) interpolation of geophysical fields, (v) temporal analysis of hydrological time series including standardization, autocorrelation function, Fourier spectrum and cross-correlations analysis with macro-climatic indices, and (vi) simulation of rainfall–runoff processes using a hydrologic distributed model. The most relevant features of HidroSIG are described in terms of the methods used for hydrologic estimations, visualization capabilities, tools for analysis and interpolation of hydro-climatic variables in space and time, geomorphologic analysis and estimation from DEMs, and other features. Water resources planning and management and diverse socio-economic sectors benefit from this freely available database and computational tool.