to which country does it belong to?
The U.S.A.
Amarillo, Texas
Amarillo ( ) is a city in the U.S. state of Texas and the seat of Potter County. 
a city in texas known for its yellow soil and wildflowers Amarillo. is this a city? Yes.
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Amarillo, Texas [SEP] Introduction
The attractions Cadillac Ranch and Big Texan Steak Ranch are located adjacent to Interstate 40. U.S. Highway 66 also passed through the city.