Claim: Iowa State Capitol, a 275 ft. high building, was the tallest building in Iowa from 1884 to 1924; then from 1991 up to the present, 801 Grand in Des Moines, which is 630 ft. high with 45 floors, holds the title.
Evidence: From its opening during 1884 until 1924, it was the tallest building in Des Moines, and likely the entire state.