Merchants Exchange Building

The Merchants Exchange Building was a massive Italianate commercial fortress at Third and Chestnut Streets, designed by Francis D. Lee and Thomas B. Annan and completed in 1875. The two-building complex measured 235 by 187 feet, and its western trading hall — with an iron truss roof spanning 235 feet unobstructed — was the largest open indoor space in the United States at the time of its construction.

The St. Louis Merchants Exchange, founded in 1836, was the first commodity trading exchange in the United States, predating the Chicago Board of Trade. It was the direct successor to the original St. Louis Chamber of Commerce and occupied the same Third and Chestnut block from 1857 onward. When the first exchange building proved inadequate, the organization held a design competition for a replacement; George I. Barnett won but his design was deemed too expensive, and the commission went to runner-up team Francis D. Lee and Thomas B. Annan. Their building opened in 1875 at a cost of $2 million. The trading hall's iron truss system created an interior 235 feet long, 98 feet wide, and 65 feet tall — the largest open indoor space in the country. That scale made it the obvious choice to host the 1876 Democratic National Convention, the first such convention held west of the Mississippi River. At the time the Exchange functioned as the financial and commercial heart of St. Louis, with daily trading sessions setting prices for grain and other commodities across the region. By the mid-twentieth century the building had long outlived its commercial prime. It was demolished in 1957–58 as part of the land clearance for the Jefferson National Expansion Memorial — the project that would eventually produce the Gateway Arch. The site sat as a parking lot before the Adams Mark Hotel was built on the block. A modernist successor Exchange building was later constructed near the Science Center in Forest Park; it too was demolished in the 1990s after the Exchange lost its building to eminent domain.