Millville is a hamlet in the town of Shelby in Orleans County, New York, United States. First settled in the mid-1810s, Millville grew as a result of the mills located there to tap the abundant water available in the three streams that run through the hamlet. In its early days, before the clearing of the land reduced the volume and regularity of the water volume in the streams, the hamlet could claim three saw mills, a grist mill and a turning mill. In the 1870s, the hamlet had an academy, three churches, a grocery, dry goods store, tannery, foundry, wagon shop, school, post office, and a cluster of about 30 houses.