Contrast that to the GOP's shrinking slice of the pie - down about 31,000 voters from three years ago.
Those numbers have Democrats looking at this fall's local elections as their best shot at wresting county control from their rivals for the first time in history. Republicans, meanwhile, are putting on a good face and hoping for the best.
County GOP Chairman Bob Kerns is not about to throw in the towel just yet.
"Registrations don't vote. People vote," Kerns said. "People will register one way or the other for a lot of different reasons. What matters are the polls, and voters have historically come out to support us."
When Democrats first took the registration edge in Montgomery County in 2008, Republican leaders blamed "Obama-mania." As in much of the nation, the chance to cast a ballot for either the first black or first female presidential candidate drew hundreds of first-time Democratic primary voters to the county's polls. Under Pennsylvania law, in order to vote in that contest, they had to register as Democrats.
GOP leaders predicted at the time that the electoral tides would soon recede and politics would continue as usual.
Montgomery County had long been considered an impenetrable Republican fortress, so much so that local business owners used to register with the party for fear of losing business. GOP registrants once outnumbered Democrats by 2-1, and the state party routinely looked toward Philadelphia's suburban hub as a source of contributions and candidates.
Last year, though, brought evidence that while the Obama high tide had indeed receded in other suburban counties, the shift in Montgomery County may be more enduring.
