It is 600.08 miles accordiing to MapQuest.
It is 644.35 miles via Fort Worth, Wichita Falls and Amarillo according to MapQuest.
600 miles taking this route:Follow U.S. 287 SOUTH from Amarillo to I-45 SOUTH to CORSICANA in Ennis, which is about 35 miles south of Dallas.Take I-45 SOUTH to Houston.
Amarillo is a city in Texas.
60.3 miles
490 miles
334 miles
The great circle distance from Amarillo to Honolulu is about 3500 miles.
Knowing exactly where in Texas would help a lot. Texas is an extremely large state, and there's going to be a substantial difference between Houston and Amarillo.
375 miles.
It is 705 miles.
725 miles
It is 650 miles according to Google Maps.