This dataset includes average, and annual average (e.g., average of 2020) watershed characteristics and environmental driver data for 189 rivers across the Northern Hemisphere. Average data includes lithology (e.g., percent of watershed covered by volcanics), land use (e.g., percent of watershed covered by cropland), maximum day length, median nitrogen and phosphorus concentrations, maximum watershed proportion of snow covered area, precipitation, temperature, evapotranspiration, green-up day, net primary productivity, 5th percentile discharge, 95th percentile discharge, day of minimum discharge, day of maximum discharge, and coefficient of variation of discharge. Average data includes maximum watershed proportion of snow covered area, precipitation, temperature, evapotranspiration, green-up day, net primary productivity, 5th percentile discharge, 95th percentile discharge, day of minimum discharge, day of maximum discharge, and coefficient of variation of discharge. Land use, lithology, snow covered area, precipitation, temperature, evapotranspiration, green-up day, and net primary productivity were sourced from public, globally available spatial datasets. Nitrogen, phosphorus, and discharge data were sourced from public and/or published datasets. Watershed characteristics and environmental variables were used in a series of random forest models to assess the drivers of 1) average fluvial silicon concentration regime; 2) annual fluvial silicon concentration regime; and 3) the minimum and maximum silicon concentrations within a given regime.