Middlesex County is included in the Hartford-East Hartford-Middletown metropolitan statistical area known as Greater Hartford.

In a few cases, neighboring towns will share certain resources, e.g. water, gas, etc.

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

Joseph E. Bibisi was the last person to serve as high sheriff of Middlesex County.

The terrain trends from mostly level along the Connecticut River and Atlantic coast to gently rolling uplands away from them.

91.1% spoke English, 2.6% Spanish, 1.9% Italian, 1.2% French and 1.0% Polish as their first language.

27.20% of all households were made up of individuals, and 10.00% had someone living alone who was 65 years of age or older.

As of the 2010 United States census, there were 165,676 people, 67,202 households, and 43,743 families living in the county.

[10] In terms of ancestry, 24.6% were Italian, 21.2% were Irish, 14.0% were English, 13.5% were German, 11.1% were Polish, and 3.4% were American.

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

Since 1948, the winning statewide candidate has also carried Middlesex County, the longest active streak in the state.