Roseto is a borough in Northampton County, Pennsylvania. The population of Roseto was 1,567 at the 2010 census. Roseto is part of the Lehigh Valley metropolitan area, which has a population of 861,899 and is the 68th most populated metropolitan area in the U.S. as of the 2020 census. Roseto is known in the fields of sociology and cardiology for the Roseto effect, wherein the close-knit Italian American community exhibited half the national average rate of heart disease in the mid-20th century.