The Sheffield Farms–Slawson–Decker Company, known as Sheffield Farms, was a dairy that pasteurized, bottled, and delivered milk in New York City in the first half of the 20th century. It became one of the largest dairy companies in the world, selling 20% of the city's milk. The company played a major part in transforming commercial milk into a clean and healthy product.
L. B. Halsey, a lawyer who married Sarah Frances Sheffield (daughter of the late John H. and Anne Maria Sheffield), became interested in the dairy business when called upon to help deliver his widowed mother-in-law’s butter. Through careful selection and breeding, the Sheffield herd of Mahwah, New Jersey, produced superior milk, which in turn made fine butter. He began marketing the butter in his spare time in the city and, by 1880, had given up the law to devote himself to the dairy trade. His first innovation was to design a covered milk wagon that protected fluid milk from dust. Halsey trained oth