Cobbs Hill Reservoir is a reservoir located in Cobbs Hill Park in Rochester, New York, United States. The reservoir is used to supply drinking water to the city of Rochester.Construction was completed in 1908. The smaller Lake Riley north of it was part of the old Erie Canal system. I-490 now runs on the old canal bed here.The land comprising modern-day Cobbs Hill Park belonged to Gideon Cobb, an earlier settler of Rochester. The land was acquired by the city through various land purchases, and donations. The largest donation was the remaining 15 acres crowning the hilltop of Cobbs Hill.The granite gatehouse atop the hill was designed by architect J. Foster Warner in Greek Revival style. The structure featured a wide portico with an ornate drinking fountain.With its surrounding iron fencing and Parisian lamp posts, the 12.8 acre reservoir further added to the landscape of Cobbs Hill. Animated by a fountain, the reservoir reportedly has the sitting capacity to fill every bath tub in Rochester, NY, twice daily, for two months.An overlook was developed in consultation with the agency of Frederick Law Olmsted— the firm responsible for creating the Rochester Parks system in the late 1880s. Olmsted executives urged the city to maintain this bluff to provide citizens with unobtrusive skyline views.