Hang on . . . let me flip a coin.
PING! Flap, flap, flap . . .
Thud . . . slap! Ummm heads . . . okay, I'll go with the passenger service airline flight.
Greater Miami is the only metropolitan area in the United States whose borders encompass two national parks.
There are a lot of NPS locations out there.
Atlanta - Kennesaw Mountain, Chattahoochie River, MLKing.
New York City - 8 listed.
Hyde Park, NY - Vanderbilt, FDR, Elenor Rosevelt
Charleston, SC - Pinckney, Sumter
District of Columbia/Baltimore metro area - too many to list.
San Francisco metro - 7 sites.
Even St. Augustine FL has a couple of sites.
The list is not exhaustive. Click here (actually, cut and paste since the link isn't clickable here) http://www.nps.gov/applications/parksearch/geosearch.cfm and search by state or zip code.