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.
From its opening during 1884 until 1924, it was the tallest building in Des Moines, and likely the entire state. 
