<P> The tallest buildings in St. Louis, Missouri, include the 630 - foot (190 m) Gateway Arch, which is also the tallest accessible structure in Missouri and the tallest monument in a national park, rising 75 feet (23 m) higher than the Washington Monument . </P> <P> The tallest habitable building in the city is the 42 - story One Metropolitan Square, completed in 1989 . At 593 feet (181 m), it is the third - tallest building in Missouri and the second - tallest habitable building . Its tenants include architecture firm Hellmuth, Obata & Kassabaum (HOK), which designed the building . The only other habitable buildings in St. Louis over 500 feet (150 m) are the One AT&T Center and the Thomas F. Eagleton United States Courthouse . </P>

What's the tallest building in st louis