Mosenthein Island, situated approximately 8miles due north of the Gateway Arch in St. Louis, Missouri, and approximately 1miles south of the confluence of the Missouri River and Mississippi River, is one of a cluster of three islands: Chouteau Island, Gabaret Island, and Mosenthein Island.[1] Mosenthein Island is 1,077 acres in area.[1] [2] The island is mainly bottomland forest.[2] It is only accessible by boat.[1] [2] It is a popular spot to camp and canoe.[3]