Virginia has them, Pennsylvania has them, but if you ask most fly-fishermen whether Maryland has any good limestone trout streams, they'll probably say no. They'll be wrong, but only by one.

Beaver Creek, just outside Hagerstown, is the Free State's lone major limestone-influenced trout stream. By great good fortune, it features several miles of public water in which to fish, including a 1 1/2 -mile stretch designated for catch-and-release fly-fishing only.

Why do we care? We care because it's February, and February is the cruelest month. It's short in duration, but drags on and on with frozen creeks and frigid, fishless bays. The beauty of limestone streams is they never freeze and never stop producing. No matter how cruddy the weather gets, you can generally find fish and the bugs they eat in these chalky waters.

"Look at all the midges," Larry Coburn, my longtime trout fishing partner, said last week as we eased along the snowy banks in our waders on a bright, crisp day. Clouds of minuscule, freshly hatched insects swarmed here and there in the dappled sunlight, and occasionally the surface of the water rippled with the slurp of a hungry trout gobbling one.

We were in the half-mile "open section" of Beaver Creek just downstream of the state's Albert Powell Fish Hatchery, a stretch in which anglers may keep two trout per day. Before the outing was over, we would bag our limits there, then move down to the catch-and-release section to hook and release several more trout on flies, including a plump 19-inch rainbow, and finish up in a section of private water in which Coburn has permission to fish, where he concluded the day by landing a trophy eight-pounder on his very last cast.

Take that, Old Man Winter.

Indeed, that final hour of fishing was spectacular by any measure, anytime, anyplace. Using spindly, three-weight fly-rods to drift salmon-egg patterns near the bottom in four feet of water, Coburn and I landed one trout after another.

After a half-dozen or so spirited tussles with scrappy rainbows of 12 to 16 inches, I'd had my fill. I took a seat on a log to soak up the lowering sun, but Coburn pressed on. "You never know when the big one might hit," he said.

There was no doubt when it did. The lunker slurped a pale orange salmon egg imitation in the deep channel but rose almost immediately to the surface, where it rolled and slapped the water with a broad, pale tail. "Whoa!" Coburn said, eyes wide.

Landing an eight-pound trout in a small stream never is easy, but it's doubly challenging on the sort of tackle at hand. A three-weight, 7 1/2 -foot rod is the whippy kind of thing you might take to the Rapidan River in July to fish for eight-inch brook trout, or to a farm pond in May to try for sunfish.

"I have to move him upstream into shallow water if I'm going to land him," Coburn said as the little rod bowed double under the pressure and threatened to snap. "I'm not sure he'll fit in my net."

The fish showed no interest in turning back upstream, so Coburn slid down the bank and into the water in his chest-high waders to pursue. Line spun off the fly-reel as the fish made a long run, then stopped and charged back upriver, Coburn reeling frantically to keep pace.

After seven or eight minutes of this sort of give-and-take, the adversaries reached a standoff. "I still have to get him set up just right to fit in the net," Coburn said. But every time he raised the rod high and bent down to net the bruiser head-on, the trout summoned another burst of energy and shot back into the deep.

On the sixth or seventh try, Coburn made his move and the big fish was secure. He scrambled up the bank for the requisite high-fives and photo opportunities, then eased the trout back in the water and waited anxiously for it to swim off, which eventually it did. "You don't want to lose 'em," Coburn said.

And that was our Feb. 21. Anyone have something better to offer?

The good news is, limestone streams such as Beaver Creek are not just productive in winter, they're good all year. When the dog days of July and August roll in with searing heat, chalk streams stay cool enough for trout to thrive, just as they remain warm enough in February. That's thanks to the natural spring that feeds them, gushing up 3,500 gallons of cool water a minute, and the limestone in it that fosters insect life.

Washington area trout anglers are familiar with the fabled limestone streams of south-central Pennsylvania -- the Yellow Breeches, Falling Spring and the Letort. And Virginians know about limestone waters in the Shenandoah Valley such as Mossy Creek, Smith Creek and the North River.

But closest of all is Beaver Creek, just over an hour's drive from downtown. Last week we saw one other angler there and just one set of footprints in the snow. It's a puzzlement.

* * *

National Capital Chapter of Trout Unlimited had its annual fly-fishing show at Bethesda-Chevy Chase High School yesterday, featuring international fly-fishing legend Lefty Kreh of Cockeysville, Md., who just turned 82. Happy birthday, Lefty.

Fly-rodders who missed that session may want to check out a free series of seminars from 10 a.m. to 4 p.m. today at the Bass Pro Shop in Hanover, where local experts Jim Gracie, Jay Sheppard, Brady Bounds, Charlie Gougeon and Coburn will offer tips and advice.