Re: Trout fishing an hour from Tysons Corner?
Potomac River is the closest. No real trout streams to speak of.
You can look at the Gunpowder River which is 90min north or Shenandoah National Park which is 2hr south. Both are fairly popular trout waters.
If you have not been to this area before, I would also consider the traffic. To get from Tyson's to the Gunpowder River would take 3hrs if you get caught traffic.