Why are Bucks and Berks county much more Republican than other counties surrounding Philly?

[King of Kensington]

Some very crude generalizations:

Delaware County:  inner-ring suburbs, largely an extension of white ethnic and Black Philadelphia

Montgomery County:  affluent/Main Line, liberal, largely Jewish

Chester County:  more WASPy affluent suburbs, trending blue

Bucks County:  mix of inner-ring suburbs and McMansions

South Jersey:  More working class and more Italian American than PA side

[King of Kensington]

Ancestry:

Bucks

German  24.7%
Irish  24.6%
Italian  15.9%
English/American  14%

Chester

Irish  23.5%
German  22.2%
English/American  15.8%
Italian  15%

Delaware

Irish  25.7%
Italian  17%
German  14.5%
English/American  11.1%

Montgomery

Irish  21.5%
German  21.5%
Italian  15.5%
English/American  12.2%

Burlington

Irish  20.2%
German  18%
Italian  16.1%
English/American  12.1%

Camden

Irish  19.1%
Italian  16.4%
German  14.6%
English/American  9.5%

Gloucester

Irish  27%
Italian  25.9%
German  21.9%
English/American  12.4%

Salem

Irish  21.1%
German  19.8%
English/American  16.6%
Italian  13.5%

Montgomery is the most Jewish county (8.1%), followed by Bucks (6.6%) and Camden (6.2%).

[King of Kensington]

College graduates

Chester  50.3%
Montgomery  47.5%
Bucks  38.4%
Delaware  36.7%
Burlington  36.4%
Camden  30.7%
Gloucester  30%
Salem  20.3%