Atmospheric deposition of reactive nitrogen (Nr) due to human activities can have measurable effects on ecosystem processing and export of nutrients, groundwater and surface-water quality, and soil microbial community structure and function. Rates of Nr deposition to lower-elevation forests immediately adjacent to the Denver/Boulder urban area, however, have only recently been measured. In conjunction with the Network for Urban Atmospheric Nitrogen Chemistry (NUANC) and the National Atmospheric Deposition Program (NADP), we are measuring wet-plus-dry Nr deposition and evaluating how spatial and seasonal variations in N deposition affect the ability of soil microbial communities to process N along an elevational gradient (1650 to 3000 meters) from plains to subalpine ecosystems west of Boulder, Colorado. Ecosystem response to atmospheric inputs of nitrogen depends on several factors, including elevational climate conditions (freeze/thaw cycles, precipitation), geology, soil and vegetation type, N speciation and microbial community structure. Ion-exchange-resin columns were deployed at 5 locations along the elevational gradient during spring, summer and fall seasons to measure bulk (wet-plus-dry) N deposition. Soil samples were collected seasonally at 3 of the locations and measured for nitrification potential and net N mineralization rates to assess the role that the microbial community plays in processing nitrogen. Results indicated that nitrification potential rates were up to 2 times greater at the lowest elevation site, where nitrogen loads and percent soil carbon and nitrogen were higher. Net N mineralization rates were 3 times greater at the highest elevation site in the fall despite lower nitrogen loads from precipitation. This research facilitates a greater understanding of the role of the microbial community in processing atmospheric nitrogen deposition in the urban-foothills transition of the Colorado Front Range.