It is a part of the St. Louis metropolitan area and Metro East in southern Illinois.

In the late 19th century the area that is now Swansea was a mix of farming and commerce.

The early residents were fiercely independent and bent on conducting their own affairs.

When the municipality that sat on their doorstep reached out to annex their lands and businesses they decided to start their own community.

Establishing an independent community was a quick and effective method of avoiding annexation.

[3] Swansea is largely flat and runs primarily in a north–south direction along the Illinois route 159 corridor.

It is bounded by Belleville to the south and west, Fairview Heights to the north and Shiloh to the east.

Swansea is home to a satellite facility of the Alvin J. Siteman Cancer Center.