Like Eddie said, many rotors are cast in China. The problem is that you cannot tell which brands are made in China.
Also, consider that many of the companies that claim their rotors are made in the USA, etc are actually buying the rough cast rotor blanks from China (they are cheaper), and they may drill the holes for the studs or machining the surfaces to their final thickness and finish, etc and then claim they are made in the USA ??? The blanks cast in China are made to the US company's exact specs and the good companies will quality test the Rotors to insure they meet their standards, but never the less, they are made in China.
A few weeks ago on Jay Leno's Tonight Show he was showing some odd/funny products or packaging. He showed a package of some inexpensive toy that said on the package: "Made in America", but the toy was clearly stamped "Made in China":angry: Perhaps the packaging was made in America???:grin:
...Rich