Samuel Cummings Jr. was born on September 23, 1734, in Stoughton, Norfolk County, Massachusetts, during a time when the region balanced between relative prosperity and lingering threats from past conflicts. As the eldest son of Samuel Cummings Sr. (1708/09–1804) and Susannah Hood (1714–1812), he grew up in a rural, agrarian community approximately 17 miles south of Boston. Stoughton, established in 1726, was known for its fertile farmland, small industries like gristmills and sawmills, and its proximity to major trade routes leading to Boston.