[2] McLean County is included in the Bloomington–Normal, IL Metropolitan Statistical Area.

Locally, the second syllable of McLean is pronounced with a 'long a' (ā, IPA /ei/) sound (i.e. "muh-KLAIN") (as with native son McLean Stevenson), not with a 'long e' (ē, IPA /i/) sound ("muh-KLEEN").

It was named for John McLean, United States Senator for Illinois, who died in 1830.

McLean County is actually larger than the land area of Rhode Island (1045 sq mi).

[6] As of the 2010 United States census, there were 169,572 people, 65,104 households, and 40,124 families residing in the county.

The only Democrats to gain an absolute majority of the county's vote before the 21st century have been Franklin D. Roosevelt in 1932 and 1936, and Lyndon Johnson by a mere 1.2% in 1964.

Woodrow Wilson in 1912 and Illinois resident Barack Obama in 2008 both carried the county by narrow pluralities.

B. Pritzker won the county by 1.3% in 2022, making it the first time since 1948 it supported a Democrat for governor.