The John Weld Peck Federal Building is located at 550 Main Street in downtown Cincinnati and you have to pass through security to see the murals. You can see pictures of the murals and of Harper working on them in Todd Oldham's Charley Harper: An Illustrated Life.
For a few more images, see Visualingual | Charley Harper Mural in the Federal Building Downtown.
MORE CHARLEY HARPER
• Charley Harper Modern Needlepoint Canvases at Purl
• Todd Oldham's Charley Harper: An Illustrated Life
• Reader's Rooms: Framed Charles Harper Prints
• Todd Oldham's Photography Portfolio
• New Charley Harper Books
• Harper's Harvest: Charley Harper Dishware