Feeling a little misty-eyed and nostalgic about Chef Itoh's passing, I'd like to begin a group project to honor the oldest restaurants in the Philadelphia area, mirroring the one we've maintained for years in Washington, DC. Surrounding areas are included, and since our community was founded on Apr 15, 2005, anything that was open on that date is included as well - an asterisk means that the restaurant is now closed (and, by definition, closed after Apr 15, 2005).
I'll start with the oldest that I know of, and will then slowly build the list over time.
1860 - McGillin's Olde Ale House
1893*- Old Original Bookbinder's (moved to Old City in 1898, the 1865 date on the sign is untrue)
1900 - Ralph's Italian Restaurant (America's oldest family-owned Italian restaurant, changed locations in 1915)
1930 - Pat's King of Steaks
1938 - Nick's Old Original Roast Beef
1960 - Dalessandro's
1964 - Casselli's (Roxborough)
1966 - Geno's Steaks
1969 - Good and Plenty (Smoketown)
1976 - City Tavern (built for our nation's bicentennial as a replica of a 1773 tavern located on Second Street)
1979 - Ishkabibble's (Queen Village)