If you mean Black Locust trees (Robinia pseudoacacia) there are plenty of them in Northern Virginia. I have one in my front yard that I let grow that's about 20 feet tall or so. The trouble with them is that they're coming up all over my yard now. They put out root suckers everywhere. They bloom in May and the flowers smell wonderful. I used to always pick some from trees I spotted while driving around. The one in my yard doesn't seem to bloom much though. All in all I'm sorry I let it grow.

And Collectordi has the general feeling about locusts... they attempt to multiply faster than dust bunnies, so folks that have them often get rid of them after a few years.

Watch as you drive in the countryside, and you'll often see them in mixed groves with sassafras, poplars, and other deciduous trees.

I love them. I love their leaves, and the pinky flowers that form in the summer. I wish I had some by me in Manassas. All we seem to have out here is an abundance of black oak trees. They drop acorns like gangbusters every other year or so. Makes walking barefoot difficult.