The effects of lakeshore development on reproductive success of Common Loons (Gavia immer) were examined in New York State’s Adirondack Park. It was hypothesized that loon reproductive success would be negatively affected by the increased amount of shoreline development that has been occurring in the Park in recent years. Additionally, it was further hypothesized that the average distance from the nest site to the nearest point of development would be greater for successful nests than for failed nests. Historical nest productivity data collected from banded Common Loons on 53 lakes over a period of 7 years were evaluated along with residential development data collected during two field seasons in 2004 and 2005. Mean distance from successful nests (n = 28) to the nearest shoreline development unit (442.7 m, Range: 41.4–1,540.0 m) was greater than the mean distance from failed nests (n = 32) to the nearest shoreline development unit (343.1 m, Range: 2.2–1,222.9 m). Presence of nesting pairs was significantly related (R² = 0.25, P = 0.001) to increased shoreline length and decreased amount of development. Common Loon chick hatching success was significantly related to the density of development on small lakes (P = 0.033), but not on large lakes (P > 0.05). Our results indicate that the amount of development on lakes is not as important to nesting Common Loons as the placement of development in clusters along lakeshores. The clustering of development on one part of the lake will allow Common Loons to nest a distance away from developed areas. Thus, this study provides additional support for the buffering of loon nesting areas from development as a conservation/ management tool to enhance their reproductive success.