Rhode Island Illustrated Patriotic Covers
Unused Civil War Patriotic Cover - Sitting Lady Liberty
Loyal to the Union - State of Rhode Island
Design by William Ridenburgh -  Nassau St., New York 

Nassau Street in New York was at one time the Center of the American Philately with over 400 dealers in stamps and paper collectables in residence. The heyday of Nassau Street began in the early 1890s although there were a few dealers there before that time. Today there are only a few dealers left on Nassau Street, most of them having moved to other locales because of the high cost of doing business in New York.

The New York Historical Society maintains a collection of several Ridenburgh Pictorial Covers
VIEW: NY Historical Society Ridenburgh Collection