If the Netherlands were a U.S. census tract, if would be #5 on the list of US census tracts as ranked by bike commuting (it would also probably surprise the Dutch).
Looking at census tracts, instead of cities, it turns out that none of the top 40 bike commuting "neighborhoods" are in the DC area. In fact only two neighborhoods, both in Philadelphia are even on the "East Coast' (for which I'm not countinig Florida).
Robert Schneider, an urban planning professor at the University of Wisconsin-Milwaukee, wanted to go beyond the city rankings. He and his assistant, Joe Stefanich, examined 60,090 census tracts to find the top 100 U.S. neighborhoods for bicycle commuting [PDF].
The paper only includes the top 40, for brevity (Boo! I boo thee brevity!) but it makes for an impressive list (see below).
Though I couldn't find any international bike commuting data for comparison, if we use bike transportation as a proxy, the top 4 US census tracts do as well or better than the Netherlands. Matching U.S. Census tracts to European countries, which is an immensely flawed comparison worthy of ridicule, I get the following
The Netherlands (36%) ~ Davis, CA (NW of UC Davis)
Denmark (24%) ~ Miami Beach, FL (S of Flamingo Park)
Hungary (23%) ~ Key West, FL (around E end of Truman Ave.)
None of the other European countries would be in the top 40.
I'd love to find the whole list of 100.
Update: Thanks to bikesnick for providing the full list in the comments. So not one neighborhood in the DC area cracked the top 100. Nor are there any in Maryland, Virginia, Delaware or West Virginia. Surprisingly there were none in NYC or Boston either. The closest top 100 neighborhoods were the 5 in Philadelphia. In order to crack the top 100, a neighborhood needed 15.7% of its residents to be bike commuters.