The county is included in the Hartford-East Hartford-Middletown, CT Metropolitan Statistical Area.

Counties in Connecticut have no governmental function; all legal power is vested in the state, city and town governments.

The office of High Sheriff in Connecticut counties was officially abolished by ballot in 2000, and corrections and court services were transferred to the state marshals.

Connecticut's eight historical counties continue to exist in name only, and are no longer considered for statistical purposes.

The ethnic and racial background of the county's population was 92.3% White, 2.7% Black or African American, 0.2% Native American, 2.3% Asian, 0.03% Pacific Islander, 1.1% from another group, and 1.4% multiracial, while 2.8% of the population were Hispanic or Latino (identifying with any race).

23.50% of all households were made up of individuals, and 7.70% had someone living alone who was 65 years of age or older.

As of the 2010 United States census, there were 152,691 people, 54,477 households, and 36,707 families living in the county.

[13] Data is from the 2010 United States Census and the 2006-2010 American Community Survey 5-Year Estimates.

In 2022, Governor Ned Lamont became the first Democrat to win Tolland County in a gubernatorial race since 1994.

Tolland County is briefly referenced in the novel Moby-Dick by Herman Melville as the place that the ill-fated African-American shipmate, Pip, comes from.