 As of 2019, Hampden County's estimated population was 466,372.Its traditional county seat is Springfield, the Connecticut River Valley's largest city, and economic and cultural capital; with an estimated population of 154,758, approximately 1 in 3 residents of Hampden County live in Springfield.Hampden County was split from Hampshire County in 1812, because Northampton, Massachusetts, was made Hampshire County's "shire town" in 1794; however, Springfield—theretofore Hampshire County's traditional shire town, dating back to its founding in 1636—grew at a pace far quicker than Northampton and was granted shire town-status over its own, southerly jurisdiction.