A "vernacular region" is a distinctive area where the inhabitants collectively consider themselves interconnected by a shared history, mutual interests, and a common identity.

Such regions are "intellectual inventions" and a form of shorthand to identify things, people, and places.

Vernacular regions reflect a "sense of place," but rarely coincide with established jurisdictional borders.

The three communities are often grouped together due to their shared history, close proximity on the Fox River, relative socioeconomic condition, and similar population sizes.

In 2011, Batavia Mayor Jeffery D. Schielke has theorized that the Tri-City moniker originated in the early 20th century from the deviation of the railroad track between Aurora and Elgin to the three cities, which conductors nicknamed the Tri-Cities.

Batavia had bid on being the host of Illinois State University but ultimately lost to Normal.