From Frederick, Gaithersburg, and Rockville via Route I-81
Follow I-81 to I-70 south toward Frederick.
Continue on I-70 to I-270 south (Exit I-270 south).
Continue on I-270 southbound to I-495 (the Capitol Beltway).
Exit onto I-495 East. Take Exit 33B Connecticut Avenue.
Go southbound on Connecticut Avenue toward Washington, D.C.
Continue southbound on Connecticut Avenue for approximately five miles.
The National Zoo will be on your left, at 3001 Connecticut Avenue.
