Geismar is an unincorporated community in Ascension Parish, Louisiana, United States and is at the heart of Louisiana's chemical corridor. The community is part of the Baton Rouge metropolitan statistical area. Geismar is south of Prairieville and west of Gonzales. The community has Three schools, Dutchtown Primary School, Dutchtown Middle School and Dutchtown High School, which are ranked among the top schools in the state of Louisiana.