Human generated emissions to the atmosphere have historically increased inorganic nitrogen (N) deposition throughout the Adirondack Mountains of New York. Nitrogen is generally a limiting nutrient for the purple pitcher plant (Sarracenia purpurea L.). Our objective was to determine the dependence of S. purpurea on atmospherically deposited and insect-derived N sources across an increasing nitrogen deposition gradient. Sampling was conducted at 10 sites, with 104 S. purpurea plants sampled. The effects of increasing nitrogen deposition on morphological characteristics and organic N content of S. purpurea and a noncarnivorous reference plant, Chamaedaphne calyculata L. Moench, Leatherleaf, were examined. Sarracenia purpurea flower and C. calyculata leaf tissues were analyzed for stable nitrogen isotope (δ¹⁵N), and foliar N content. Increased nitrogen deposition up to 4.1 kgN*ha⁻¹*yr⁻¹ was correlated with increased plant size and δ¹⁵N values of S. purpurea. However, deposition exceeding these levels decreased overall plant size and δ¹⁵N values. Nitrogen derived from assimilation of insects ranged from 55% to 90% of foliar N at higher N deposition levels. Plants that acquired the greatest amount of N from insect consumption were also the largest plants. These results reflect the importance of monitoring ecologically sensitive species, like S. purpurea, in light of anthropogenic sources of pollution.