  greene county is a county located in the u.s. state of pennsylvania. as of the 2010 census, the population was 38,686. its county seat is waynesburg. greene county was created on february 9, 1796, from part of washington county and named for general nathanael greene. greene county is part of the pittsburgh dma. it is located in the area of southwestern pennsylvania that was formerly claimed by virginia, the district of west augusta. ==geography== according to the u.s. census bureau, the county has a total area of , of which  is land and  (0.36%) is water. ===adjacent counties=== *washington county (north) *fayette county (east) *monongalia county, west virginia (south) *wetzel county, west virginia (southwest) *marshall county, west virginia (west) ==demographics==  as of the census of 2
1796_establishments_in_the_United_States Counties_of_Appalachia Greene_County,_Pennsylvania Pennsylvania_counties