I use Dr. Gold at Chadwell Animal Hospital in Harford Co MD.

http://www.chadwellanimalhospital.com/



Here is something else I got off a yahoo list:
Here you go: (a copy from REPTILES Mag.)
Gary A. Schwartz, DMV., treating reptiles/amphibians in the
Maryland/Washington DC metro area. Boarding facilities provided.
Wheaton Animal Hospital (301) 949-1520.

AND

From: kaszyn

What part of Maryland? There is a good herp vet in Gaithersburg...Dr.
Debbie Alls-Temples at Gaithersburg Animal Hospital...301-948-2828. She's
very knowledgeable about reptiles and has helped me salvage a monitor and
several prehensile-tailed skinks. Never had to bring a turtle there
though.