With LED flashlights, it's fairly hard to find Made in USA because things like LEDs and circuit boards may be made elsewhere.
Assembled in USA is more common, and Maglite and SureFire are two that will always be assembled in USA (either due to company philosophy or government order requirements). Streamlight's rechargeables are assembled in USA, but others, such as the PT-series, may not be (it can easily be checked, their online Info Sheets mention country of origin). Pelican's lights are assembled in USA. I've heard that Inova may be assembled in USA, but my T4 wasn't.
It's not easy to find Assembled or Made in USA, so when possible, I try to stick with domestic. These products usually come with lifetime warranties, which is a real plus. A warranty of only a couple years indicates how much confidence the company has in their product (things like flashlights should be able to last a long time), and dealing internationally is just going to be an expensive headache.