The National Watch and Clock Museum

"The National Watch and Clock Museum [in Columbia, Pennsylvania] was officially opened to the public in 1977 with fewer than 1,000 items. Since that time, the collection has increased to over 12,000 items and the museum has undergone several expansion projects. The latest expansion opened in October 1999 and featured an entirely new and redesigned exhibit space, as well as a new two-story addition. Today, the museum is recognized as the largest and most comprehensive horological collection in North America." Link