Cheshire County comprises the Keene, NH micropolitan statistical area.

[3] The highest point in Cheshire County is Mount Monadnock, in the northwestern part of Jaffrey, at 3,165 feet (965 m).

As of the census[9] of 2000, there were 73,825 people, 28,299 households, and 18,790 families living in the county.

There were 31,876 housing units at an average density of 45 per square mile (17/km2).

The county's racial makeup was 97.75% White, 0.37% Black or African American, 0.31% Native American, 0.47% Asian, 0.04% Pacific Islander, 0.18% from other races, and 0.89% from two or more races.

25.50% of all households were made up of individuals, and 9.60% had someone living alone who was 65 years of age or older.

As of the 2010 United States census, there were 77,117 people, 30,204 households, and 19,284 families living in the county.

There were 34,773 housing units at an average density of 49.2 per square mile (19.0/km2).

[10] In terms of ancestry, 20.7% were English, 19.1% were Irish, 12.0% were German, 8.8% were French Canadian, 8.7% were Italian, 5.0% were Scottish, and 4.7% were American.