The city lies in gently rolling terrain, between Joachim Creek to the northwest and Plattin Creek to the southeast. The original core of the community is situated slightly to the northeast, immediately west of Crystal City, with most of the newest development occurring west of I-55. Festus has a total area of 5.71 square miles, and an average elevation of 433 feet.<ref>https://web.archive.org/web/20120702145235/http://www.census.gov/geo/www/gazetteer/files/Gaz_places_national.txt</ref> | The city lies in gently rolling terrain, between Joachim Creek to the northwest and Plattin Creek to the southeast. The original core of the community is situated slightly to the northeast, immediately west of Crystal City, with most of the newest development occurring west of I-55. Festus has a total area of 5.71 square miles, and an average elevation of 433 feet.<ref>https://web.archive.org/web/20120702145235/http://www.census.gov/geo/www/gazetteer/files/Gaz_places_national.txt</ref> |