18TH Congressional District:

 

Allegheny County:

Bethel Park
Bridgeville
Carnegie
Castle Shannon
Collier Twp
Crescent Twp
Edgeworth
Elizabeth Boro
Elizabeth Twp
Findlay Twp
Forward Twp
Heidelberg Boro
Jefferson Hills
Leet
Leetsdale
McDonald Boro
Monroeville
Moon Twp
Mt Lebanon
North Fayette
Oakdale Boro
Pennsbury Village
Pleasant Hills
Robinson Twp
Rosslyn Farms
Scott Twp
South Fayette
South Park
South Versailles
Thornburg Boro
Upper St. Clair
West Elizabeth
Whitehall Boro

Greene County:

Aleppo Twp
Center Twp
Franklin Twp
Freeport Twp
Gilmore Twp
Gray Twp
Jackson Twp
Morgan Twp
Morris Twp
Perry Twp
Richhill Twp
Springhill Twp
Washington Twp
Wayne Twp
Waynesburg
Whiteley Twp

Washington County:

Amwell Twp
Beallsville
Blaine Twp
Buffalo Twp
Burgettstown
Canonsburg
Canton Twp
Cecil
Chartiers Twp
Claysville Boro
Cokeburg
Cross Creek Twp
Deemston
Donegal Twp
Fallowfield
East & West Finley Twps
East Washington Boro
Ellsworth
Finleyville
Green Hills
Hanover Twp
Hopewell Twp
Houston
Independence Twp
Jefferson Twp
Marianna
McDonald Boro
Midway Boro
Morris Twp
Mt Pleasant Twp
North Bethlehem
North Franklin Twp
North & South Strabane Twps
Nottingham Twp
Peters Twp
Robinson Twp
Smith Twp
Somerset
South Franklin Twp
Union Twp
City of Washington
West Bethlehem
West Middletown Boro
West Pike Run

Westmoreland County:

Adamsburg Boro
Arona Boro
Cook Twp
Donegal Boro
Donegal Twp
East Huntingdon Twp
Greensburg
Hempfield
Hunker Boro
Irwin Boro
Jeannette
Latrobe
Laurel Mountain Boro
Ligonier Boro
Ligonier Twp
Madison Boro
Manor Boro
Mt. Pleasant Boro
Mt Pleasant Twp
New Stanton
North Huntingdon
North Irwin
Penn Boro
Penn Twp
Rostraver Twp
Scottdale
Sewickley Twp
Smithton
South Greensburg Boro
South Huntingdon Twp
Southwest Greensburg Boro
Sutersville Boro
Trafford Boro
Unity Twp
West Newton
Youngstown Boro
Youngwood Boro