In 1790, Massachusetts administered the first Federal census under the new United States Constitution that required every state to enumerate and report its population every 10 years to determine the number of representatives a state can send to the United States House of Representatives. Organized by town, census takers used the same form, beginning with “Names of Heads of Families” and counting individuals in a household who fell within the following categories: “Free white Males of 16 years and upwards”; “Free white Males, under 16 years”; “Free white Females”; “All other free Persons”; and “Slaves”. In the census of 1790, Massachusetts reported its total population, including what later became the state of Maine, to be 484,327—about 10% of the total population of the United States at that time. The original manuscript of the Massachusetts 1790 Federal census was used to create this published version in the Pocumtuck Valley Memorial Association Library.