With 96 percent of precincts reporting late Tuesday, Dean had a solid lead over Sharpton, the only Democratic candidate who campaigned heavily in the district in the race's closing days.
For many participants the primary was more a protest against the city's lack of congressional representation than about electing the party's next presidential nominee.
Most candidates skipped the D.C. race or focused time and money elsewhere. The balloting has no direct effect on the city's allocation of delegates to the Democratic National Convention; they will be selected in party caucuses in February and March.
About 15 percent of eligible voters cast ballots, more than other recent presidential primaries in the city but far below the number who typically vote in races for mayor or in general elections for president.