Current and historical voter registration statistics for Pennsylvania can be viewed
here.
Between 11-06-2007 and 04-06-2008, the number of registered Democrats increased from 3,883,378 to 4,190,064. This represents a net increase of 306,686 (7.9%). The number of Democrats increased in 66 of Pennsylvania's 67 counties, decreasing only in Venango (rural county in NW part of state).
The biggest net increases by magnitude were in the following counties:
- 49,533 - Philadelphia
- 28,173 - Montgomery (NW of Philadelphia)
- 25,512 - Allegheny (includes Pittsburgh)
- 21,924 - Delaware (W of Philadelphia)
- 19,842 - Bucks (N of Philadelphia)
- 19,599 - Chester (W of Delaware County, still considered Philadelphia suburbs/exurbs)
- 13,168 - Lancaster (south-central PA)
- 9,671 - York (south-central PA, S of Harrisburg)
- 9,006 - Dauphin (includes Harrisburg)
- 8,561 - Lehigh (includes Allentown)
The biggest net increases by percentage were in the following counties:
- 21.2 - Chester
- 19.6 - Centre (central PA, includes Penn State)
- 17.3 - Union (central PA, includes Bucknell University)
- 16.5 - Cumberland (south-central PA, SW of Harrisburg)
- 16.5 - Delaware
- 16.2 - Lancaster
- 14.3 - Lebanon (south-central PA, E of Harrisburg)
- 13.0 - Montgomery
- 12.8 - Dauphin
- 12.1 - Wayne (rural county in NE corner of state)
During the weeks of 01-01-2008 through 03-31-2008, 209,903 new voters registered in Pennsylvania. Of those, 146,166 (69.6%) registered as Democrats. 18.5% registered as Republicans, and 11.9% registered as some other party or unaffiliated. New Democrats outnumbered new Republicans in 63 of 67 counties. The remaining 4 (Bedford, Cameron, Juniata, and Potter) are all rural counties with small populations.
During those same weeks, 160,752 voters changed their registration to Democratic, 11 times more than the 14,716 who changed their registration to Republican.
As of 04-06-2008, 50.4% of Pennsylvania voters were registered as Democrats, 38.3% as Republicans, and 11.3% as some other party or unaffiliated. Among those age 18 to 24, 52.6% were registered as Democrats, while only 29.3% were registered as Republicans and 18.1% as some other party or unaffiliated.