Question: Scottsbluff is a city in Scotts Bluff county, that is part of what region of the United States that is covered in prairie, steppe, and grassland, and lies east of the Rocky Mountains?
Sentence (from "Western Nebraska Regional Airport"): Western Nebraska Regional Airport (IATA: BFF, ICAO: KBFF, FAA LID: BFF) (William B. Heilig Field) is three miles east of Scottsbluff, in Scotts Bluff County, Nebraska.
Relevant evidence: No