[2] Rostraver Township is in the southwestern corner of Westmoreland County and is the location of the Household No.

[4] The name of the township has been traced back to Rostrevor, a seaside community in County Down, now in Northern Ireland.

It is known that some of the early settlers, such as the McClains, came from County Down so it is surmised that they probably named their new community out of affection for the native village and spelled it phonetically as Rostraver[5][6] Unfortunately, they neglected to leave to posterity any record of having done so.

Across the Monongahela River to the west, Rostraver runs adjacent with six Washington County neighborhoods, including (from north to south): Carroll Township, Donora, another segment of Carroll Township, Fallowfield Township, North Charleroi, Charleroi, and Speers (connected by the Belle Vernon Bridge on I-70).

Across the Youghiogheny River to the east, Rostraver runs adjacent almost entirely with South Huntingdon, the exceptions being Sewickley Township, West Newton and Smithton.

Rostraver Township is also home to the Belle Vernon Barracks of the Pennsylvania State Police, which is located on Circle Drive.