Orange County, California is 8 times larger than Amarillo, Texas.
Area: 257 km2 calculated
Amarillo is the fourteenth most populous city in the state of Texas, also the largest City in the Texas Panhandle, and the seat of Potter County. A portion of the city extends into Randall County. The population was 190,695 at the 2010 census. Wikipedia
Area: 2,064 km2 calculated
Orange County is a county in the U.S. state of California. As of the 2010 census, the population was 3,010,232 making it the third-most populous county in California, the sixth-most populous in the United States, and it more populous than twenty-one U.S. states. Its county seat is Santa Ana. Wikipedia