Security Bank Building, Sioux Falls

The Security Bank Building, also known as the Security Building, stands as a historic landmark on South Main Avenue in downtown Sioux Falls. Constructed in 1916, it holds the distinction of being the first steel-framed office building in the state, a significant architectural achievement of its time.

Designed by the E. Jackson Casse Company in the Classical Revival style, the six-story building features Ionic columns at its main entrance, a Bedford limestone facade, and decorative elements on its cornice and shed roof. Its steel-frame construction allowed for a taller, more durable structure, making it one of the most prominent buildings in early 20th-century Sioux Falls. Over the years, two additions were made to the south side-one in 1951 and another in 1957-to accommodate growing business needs.

Aside from its architectural significance, the Security Bank Building gained national notoriety as the site of a bank robbery by the infamous John Dillinger Gang on March 6, 1934. The gang, led by FBI Public Enemy No. 1, stormed the building's grand two-story banking hall, escaping with $50,000.

Originally constructed as the headquarters for the Security National Bank, the building has undergone multiple transformations. The 1970s saw the removal of its original banking lobby, but in 2007, a $6.4 million renovation restored much of its historic grandeur. The upper floors were converted into luxury apartments, while office spaces and professional suites were reopened. This redevelopment was part of broader revitalization efforts in downtown Sioux Falls, ensuring that the Security Bank Building remains a symbol of resilience, history, and architectural prestige in the city.

Added to the National Register of Historic Places in 1984, the Security Bank Building continues to stand as a testament to Sioux Falls' growth, architectural ambition, and its unexpected brush with outlaw history.