Mule deer, like this one, and whitetails as well, roam Sinlahekin GMU 215. Photo by David Michael Jones.

About the time the aspens in the draw start turning yellow, the only thing I can think about is hunting deer -- glassing, chasing monster bucks through rocks and shrubs, trying to get a shot.

You pass it off as an annual case of buck fever. But it's pretty bad, and as far as I know, there's only one cure.

I open my trunk and toss in my baggage. I lay my rifle flat in the back seat, a box of shells on the dash. Then I'm heading for somewhere off the map, where the road is made of dirt and mule deer hunting is worth it.

I've got a clean tag, a good pair of boots, and I'm not stopping until I get to Sinlahekin country.

Far from the city lights, Washington's Sinlahekin Valley is about as close to the big skies of Montana as you can get without crossing the border. It takes effort to get there, but the mule deer hunting is topnotch. It could be the best-kept deer-hunting secret in the state.

In 2005, Sinlahekin Game Management Unit 215 yielded 340 bucks to deer hunters, which puts it among the top-producing units in the state. Beyond those good numbers, we're hearing of more bucks with trophy dimensions in this GMU.

So why aren't more hunters making the trip? That's just what I've been wondering.

DEER-HUNTERS' HEAVEN
Created in 1938, the Sinlahekin Wildlife Area is the oldest wildlife area in the state. Originally established to provide habitat for wintering mule deer, the valley has become a haven for all kinds of birds and animals. This is a coulee, deeply glaciated. It has a vertical relief of more than 3,500 feet in some areas. The valley floor is more gently folded, with pine forests on the flanks, and the willow, osier dogwood, and cottonwood mix that accompanies most of the river bottoms on the dry side of the state.

Sometime in the 1950s, the game department experimented with plantings of exotic shrubs, attempting to augment deer browse. Many of the trials did not pan out, but some of the food plots are still evident.

Today, wildlife area managers maintain alfalfa and grain crops for the sake of the big-game animals.

GETTING THERE
Unless you live in Loomis or Tonasket, chances are you'll need to do a piece of driving to get on location. The Sinlahekin River valley is oriented north and south between the small towns of Loomis and Conconully in Okanogan County.

Get there from State Route 97 by turning west on the South Pine Creek Road (milepost 305) near Riverside. The roads are dusty, but normally in good condition for two-wheel-drive vehicles.

Take South Pine Creek Road west about seven miles where it enters the Wildlife Area near Fish Lake. Just past the lake, the road veers right and continues north, cutting through 15 miles of awesome hunting territory, all the way to the town of Loomis.

Campsites are primitive, but abundant. Fish Lake has more than 50 established sites, many large enough for hunters with trailers. Blue Lake, to the north, is good for another 32 sites, while Forde and Conners lakes, on the far north end of the valley, have 30 more sites combined. All along the Sinlahekin Valley Road there are various primitive hunter camps for parties who rough it.

The 2007 modern firearm season for GMU 215 runs from Oct. 13 through 21. Mule deer must have at least three antler points on one side to be legal. Hunters must possess a valid, modern-firearm deer tag, and wear hunter orange while in the field. The Sinlahekin Unit is also open for any whitetail buck at the same time.

Archers can enjoy a generous late hunt from Nov. 20 through Dec. 8, for the taking of any white-tailed deer or mule deer bucks with three or more antler points on one side.

Don't be surprised to come across whitetails. The valley floor contains habitat they favor, and it is quite populated. You can expect whitetails to travel in the early mornings to bedding places several hundred feet above the river. There's plenty of water in the valley, but not much on the steep hillsides surrounding it.

Some hunters prefer to hunt for a mule deer trophy during the first half of the trip, and then switch to the any-legal-buck policy in the bottom of the ninth inning.

BITTERBRUSH IS KEY
Mule deer in the Sinlahekin Unit commonly feed on bitterbrush at night and during the early morning hours. Staying in the valley floor is probably not the best approach for mule deer, since during hunting season, they will tend to be high up on the ridges and in the rocks.

Go high and find bitterbrush, and you'll find mulies. Bitterbrush is a full-sun plant. You'll find it growing predominantly on south-facing ridges, or near rocky outcrops.

Find yourself a ridge with bitterbrush on the south face, and timber on the north, and work it hard. Bucks will feed on the sunny side during the night, then begin looking for cover by daybreak. At first light, therefore, the edge of the timber is the place to be. Bucks will often travel or bed down within 100 yards of timberline -- so flirt with the edge, then step in farther and work it over well.

The draws in the valley are typically well-vegetated, making good travel corridors for wary deer. Don't skimp on binoculars. You'll need to glass every square inch of the brushy draws to catch them moving through.

If you buy a good pair of optics, you'll see more deer. If you find a good corridor, put on a warm jacket and spend plenty of time sitting and glassing. There might be other hunters pushing deer through the area, and the draws with pockets of shrubs and trees will best encourage startled deer to move your way.

The Sinlahekin Wildlife Area provides habitat for migrating mule deer traveling southeast from the Pasayten Wilderness. There's a vastness of big mule deer country up above Toats Coulee Creek in places like Horseshoe Basin, Windy Peak, and Cathedral Pass near the Canada border. Much of this area is like tundra parkland, rolling on for miles and miles.

Come October, new bucks begin filtering down toward their winter range. Even if the weather is fair, you can expect a few newcomers. And if there's been a summer drought, you might be surprised at how many good bucks show up by mid-October.

If you are super-lucky, and a deep snow hits the Pasayten early, look for migrating herds to arrive within 24 hours. Archery hunters, with their lengthy late season, are more likely to see the full migration take shape.

Busting into the rocks, high above the valley, isn't a bad idea -- if you have the boot leather for it. Some of the heaviest-horned animals from Sinlahekin come from hidey-holes in the rock outcroppings.