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?

Context paragraphs:
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.  The airport is owned by the Airport Authority of Scotts Bluff County.  It sees one passenger airline, subsidized by the Essential Air Service program.

Gering, Nebraska: Gering is a city in Scotts Bluff County, Nebraska, United States.  The population was 8,500 at the 2010 census.  It is the county seat of Scotts Bluff County.

Morrill, Nebraska: Morrill is a village located in Scotts Bluff County, in the western Panhandle, in the northwestern portion of the United States state of Nebraska.  Morrill is part of the Scottsbluff, Nebraska Micropolitan Statistical Area.  The population was 921 at the 2010 census.

Scottsbluff Public Schools: Scottsbluff Public Schools, located in Scottsbluff, Nebraska, United States, is the largest school district in Scotts Bluff County.  The district serves more than 2,600 students and has one high school, one middle school, and six elementary schools.

Minatare, Nebraska: Minatare (Hidatsa: "mirita'ri"; "crosses the water") is a city in Scotts Bluff County, Nebraska, United States.  It is part of the Scottsbluff, Nebraska Micropolitan Statistical Area.  The population was 816 at the 2010 census.

Melbeta, Nebraska: Melbeta is a village in Scotts Bluff County, Nebraska, United States.  It is part of the Scottsbluff, Nebraska Micropolitan Statistical Area.  The population was 112 at the 2010 census.

Mitchell, Nebraska: Mitchell is a city in Scotts Bluff County, Nebraska, United States.  It is part of the Scottsbluff, Nebraska Micropolitan Statistical Area.  The population was 1,702 at the 2010 census.

Scottsbluff, Nebraska: Scottsbluff is a city in Scotts Bluff County, in the western part of the state of Nebraska, in the Great Plains region of the United States.  The population was 15,039 at the 2010 census.  Scottsbluff is the largest city in the Nebraska Panhandle, and the 13th largest city in Nebraska.

Terrytown, Nebraska: Terrytown is a village in Scotts Bluff County, Nebraska, United States.  The population was 1,198 at the 2010 census.  It is part of the Scottsbluff, Nebraska Micropolitan Statistical Area.  Terrytown is located on the bank of the North Platte River between the cities of Scottsbluff and Gering, Nebraska.  Separated only by the river, Scottsbluff and Gering have grown together to form the 7th largest urban area in Nebraska, which incorporates the small village of Terrytown as well.

Great Plains: The Great Plains (sometimes simply "the Plains") is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada.  It embraces

Supporting paragraphs: Scottsbluff, Nebraska Great Plains
Answer: The Great Plains