Its traditional county seat and most populous city is Greenfield.

[2] Franklin County comprises the Greenfield Town, MA Micropolitan Statistical Area, which is included in the Springfield-Greenfield Town, MA Combined Statistical Area.

Counties in Massachusetts and New England generally are historically weak governmental structures.

Communities are permitted to form regional compacts for sharing services.

[6] The regional council provides various services on a regional basis, and a majority of the county's towns are members of the Franklin County Solid Waste Management District, which provides municipal waste disposal and recycling services to its members.

[9] Central and southern Franklin County is dominated by the northern end of the Pioneer Valley, with steep hills rising on either side of the Connecticut River.

The high point of Franklin County is Crum Hill, 2,841 feet (866 m), located in the town of Monroe.

The climate in Franklin County is typically cool temperate.

There were 31,939 housing units at an average density of 46 per square mile (18/km2).

The racial makeup of the county was 95.40% White, 0.89% Black or African American, 0.29% Native American, 1.04% Asian, 0.03% Pacific Islander, 0.75% from other races, and 1.61% from two or more races.

Most of those claiming to be of "American" ancestry are actually of English descent, but have family that has been in the country for so long, in many cases since the early seventeenth century that they choose to identify simply as "American".

There were 33,758 housing units at an average density of 48.3 per square mile (18.6/km2).