A fresh snow falls overnight. Canyons turn white and silent. That's when we start noticing tracks. They're everywhere: boot prints of two, three, maybe four men. We never actually see them. They are either just ahead of us, or just behind, their trail picked up as we backtrack or as we drop to a canyon floor.

This is where the classic American notion of wilderness collides with the reality of a landscape. The Wilderness Act defines areas "where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain." But how real has that kind of place ever been? I convince myself the tracks must belong to hunters, probably out with rifles looking for mule deer. At one point we find their boot prints side-by-side in the snow where they each gazed in the same direction: the route Colin and I had just come down. They know we are here.

We change the way we move, try to make ourselves invisible, traveling away from animal trails through a busted topography of fallen cliffs and deeper canyons. In the evening, I walk by myself along a canyon made of soaring rock and massive columns of fir. It is last light, and the forest looks pointillist, nothing solid enough to seem real. I reach a water hole, punch through the ice, fill my bottles. Loping back to camp with fresh supplies, shadows grow thick and I move faster. Everything has eyes. Was this in the Wilderness Act, too?

In the morning, Colin and I decide to switch course again, getting away from the tracks by jumping to a different network of canyons. He scouts a clean route -- fresh snow and not a single track to be seen. We can drop into this canyon and eventually angle our way to the nearest highway, thumb our way out.

I smile and thank him, feel weight lifting off me. But the moment we shoulder our packs, successive pops of an automatic weapon ring out around us. The gunfire comes from the canyon ahead, the place Colin just came from. Eight or ten shots; it is not someone out for deer. Not even knowing if we have been spotted, we sprint back the way we came, throwing ourselves down chimneys of rock where the people before the Navajo once carved handholds. We monkey our way to the bottom, arriving in time to set camp among yet more tracks -- this time from a mountain lion. They're fresh, paced back and forth, hungry. I sleep that night with my knife blade unfolded and locked in my sleeping bag, unsure whether it's for the lion or for whatever I feel haunting these canyons. Can you slash through a ghost?

It might be simple paranoia. Maybe nobody actually knows we are here, just a coincidence of footsteps and gunfire. There might not be such things as ghosts and coyotes who walk on two legs. Still, I feel stared at, naked.

The next day, we try another exit down a new canyon in a dawn blizzard. The mesa widens, empties our canyon out into a broad and blustery sky. Sheep bells jangle around the bend ahead of us. Hauling big winter packs, bearded and crazy-looking, we prepare for our first face-to-face, rehearsing words that we hope will garner forgiveness for our trespass. But there's not even a dog to lift its ears at us. Only sheep, and they do not seem to notice our passage, as if we were transparent.

A hogan appears through the snow ahead, smoke flying sideways out its stovepipe. A red, threadbare blanket flaps on a line outside. Don't come to the window, I think. There is nothing out here but the wind.

We walk single file, our eyes straight ahead, and the hogan passes. Champagne-snow billows across the ground, taking the entire landscape in and out of view. Colin and I appear, disappear. By the time we reach the highway, we have crashed through creek ice, and mud is spattered to our waists. We put out our thumbs and watch Anglos race past, none willing to give us more than a shocked glance.

Finally, a wobbly red pickup pulls over. A family sits up front, an older Navajo man at the wheel, plump, round smile on his face. He looks like he has a little Hopi in his blood, true Native all around. We hop in the back, newcomers with hands folded into our armpits. We wanted to learn this place, and now we know there is wilderness deeper than the one imagined by Muir and Thoreau with their rucksacks and crusts of bread.

The truck starts up and asphalt rolls away, yellow line flashing past. Our tracks are obliterated, the line cut. We are all ghosts around here, the canyons holding a memory of our passage, adding us to centuries of people who came to either settle or disappear. I put my head down against stinging flurries of snow as this country of red mesas floats away.

Craig Childs writes from Crawford, Colorado.