I have permits from three states and did the research to see where the reciprocity was within the states. Washington DC doesn't have reciprocity with any state that I can find. I'm good in about 40 states but not in DC.
The District of Columbia is the only jurisdiction left in the nation that has a blanket prohibition on the carry of guns outside of the home:
http://gunwatch.blogspot.com/2013/09/justice-deniedsecond-amendment-case.html