The Pioneer Valley Transit Authority (PVTA) oversees and coordinates public transportation in the Pioneer Valley of Western Massachusetts, offering fixed-route bus service, paratransit service, and senior van service. PVTA was created by Chapter 161B of the Massachusetts General Laws in 1974. Based in Springfield, Massachusetts, PVTA serves Hampden and Hampshire counties, and provides connecting service to CTtransit in Hartford County, Connecticut, to FRTA in Franklin County, and to WRTA in Worcester County. It is the largest regional transit authority, and second largest public transit system in Massachusetts after the Massachusetts Bay Transit Authority, providing service to over 11 million riders annually across 24 municipalities in the region, with about 70% of all riders using the system as their primary mode of transit.

Hampshire County is a historical and judicial county located in the U.S. state of Massachusetts. As of the 2020 census, the population was 162,308. Its most populous municipality is Amherst, its largest town in terms of landmass is Belchertown, and its traditional county seat is Northampton. The county is named after the county Hampshire, in England. Hampshire County is part of the Springfield, MA Metropolitan Statistical Area. Together with Hampden County, Hampshire County municipalities belong to the Pioneer Valley Planning Commission.