The Merchants' National Bank (1914) building is a historic commercial building located in Grinnell, Iowa. It is one of a series of small banks designed by Louis Sullivan in the Midwest between 1909 and 1919. All of the banks are built of brick and for this structure he employed various shades of brick, ranging in color from blue-black to golden brown, giving it an overall reddish brown appearance. It was declared a National Historic Landmark in 1976 for its architecture. In 1991 it was listed as a contributing property in the Grinnell Historic Commercial District.