Surprising even many Democrats, John F. Kerry trounced George W. Bush in Fairfax County even as the president was winning a convincing victory in Virginia and the nation.

It was the first time Fairfax voters favored the Democratic presidential nominee in 40 years. The Massachusetts senator won the county handily, beating Bush in 158 of 225 precincts and in seven of the nine magisterial districts.

Many reliably Republican precincts that had backed Bush in 2000 switched to support the Democrat this time, bucking the national trend. These were precincts such as Aldrin in north Reston, which gave Kerry a 297-vote edge even as it rejected incumbent Rep. James P. Moran Jr. (D-Va.) by 220 votes. Aldrin is in the Hunter Mill District, which Kerry carried by 7,108 votes, his largest plurality among the magisterial districts.

Bush did best in the Springfield District, where the president tallied a 4,357-vote edge over Kerry, and in the Sully District, where the Republican had a 2,911 vote plurality.

Precincts carried by Bush in 2000 but won by Kerry in 2004 are indicated with an asterisk. There were no precincts that changed from Democrat in 2000 to Republican in 2004. Several new precincts were added this year, reflecting increases in the county's population.