The community is part of the Baton Rouge metropolitan statistical area.

Geismar is south of Prairieville and west of Gonzales.

[2] The Mississippi River flows to the southeast along the southwest side of the community.

The area is vulnerable to hurricanes and tropical systems due to its low elevation and its proximity to the coast of southeast Louisiana.

On the morning of June 13, 2013, an explosion occurred at the Williams Olefins plant[3] in Geismar.