The River Aln forms its unofficial northern boundary.

Sannauk Forest Preserve serves as the unofficial boundary between Somonauk and Sandwich, which resides to the east.

Route 128 is sometimes regarded as the unofficial boundary of the Greater Boston region, especially to the north and south.

Indeed, unofficial boundaries provide stark divisions between whites and blacks through much of Chicago, as they do in New York and many other cities.

The road forms an unofficial boundary to Wapping, which lies between the River Thames and The Highway.

The unofficial boundary is generally considered to be the public school district served by Robertsdale High School.

Interstate 5: Interstate 5 forms much of the eastern city limit, acting as an effective, though unofficial boundary between Eugene and Springfield.

The Billerica Mills Historic District lies entirely within the village's unofficial boundaries.

This winding street, which more or less follows the line of the old Roman wall, is the unofficial boundary of the Barri Gòtic.

When he crossed the unofficial boundary between their camp and that of the ogres, it was the same.