Merchants' National Bank

NW corner 4th Ave. and Broad St., Grinnell, Iowa

One of Louis Sullivan's "Jewel Box" banks and one of the best preserved.


Merchants' National Bank


Photo from the Historic American Buildings Survey

View photos at Library of Congress


Street View 


One of the three best preserved of the small midwestern banks built by Sullivan. -- Historic American Buildings Survey (HABS IA-77)

In the twilight of his career, Louis Sullivan designed several small office buildings and a department store in Clinton, Iowa. But his farewell gift to architecture was comprised of eight bank buildings commissioned from around the Midwest. He dubbed the designs "Jewel Boxes" for their simple but strong external appearance, with the security shown for the gems locked firmly inside.

When asked why the bank should buy his design, far more expensive than other architect's building designs, Sullivan replied, "A thousand architects could design those buildings. Only I can design this one."

The eight "Jewel Boxes" still exist and some still house banking operations. Sullivan once said, "It is the pervading law…that form always follows function. This is the law." The fact that his 100 year old bank designs still function as banks proves his point - form always follows function.

This Jewel Box is a prime example of Sullivan's genius.

National Register information 

Posted to the National Register of Historic Places on January 7, 1976
Reference number
Architectural styles
American Movement; Other architectural type; Sullivanesque
Area of significance
Level of significance
Evaluation criteria
C - Design/Construction
Property type
Historic function
Financial institution
Current function
Financial institution
Periods of significance
1900-1924; 1975-2000
Significant years
1914; 1976

Update Log 

  • August 26, 2013: New Street View added by Dave King
  • May 5, 2013: Updated by J.R. Manning: Corrected GPS Coordinates
  • April 29, 2013: New photos from J.R. Manning
  • February 5, 2013: New photo from Ray Kasal
  • July 27, 2011: New photo from Ray Kasal