Across the rugged mountain valley where Ed Depaoli has spent a lifetime raising cattle, the latest obstacles blocking the path of his herd almost bring tears to his hard old cowboy eyes.

Gleaming, sprawling homes keep rising up from the fields of sagebrush, a few dozen miles from the nearest town or paved road. The pace of development is turning his cattle runs into a clumsy march through a maze of settlers who are strangers to the land and who often do not take kindly to seeing livestock wandering through their new back yards.

In the past year, Depaoli has found two of his cows shot dead. Others have been fired on or chased by all-terrain vehicles. He and other ranchers are urging newcomers to erect fences around their property, but some refuse. One remote pasture where his herd once roamed has been transformed into an ultimate sign of the new West--a giant warehouse for the Internet retailer Amazon.com.

"It's a crying shame," Depaoli said one recent afternoon as he drove his banged-up old truck along a dirt trail winding deep into the Palomino Valley, which is about 40 miles north of Reno. "It makes you wonder how long we'll last. To tell you the truth, sometimes I don't really know why I even fool with it anymore."

Ranchers across the rural West, whose population is growing at one of the fastest rates in the nation, have the same lament. The range, they say, hardly feels like home anymore.

Here in Washoe County where the Pony Express once rode, and throughout the expanse of northern Nevada, the emergence of large weekend homes and plush townhouse developments lining highways with old-West names like Bridle Path are sights that many welcome. They are signs of a robust economy, more jobs and a stronger tax base. But the boom has other consequences.

For ranchers, it means that the spirit and identity of the region also is changing--a shift from cows to condos, they call it. And with fear that a way of life that has defined the West is at risk of disappearing, many of them have begun making what looks like a last stand.

At the urging of cattlemen in the state, the Nevada legislature recently upgraded the crime of harming or even harassing a cow from a misdemeanor to a felony. That move followed several incidents of random violence against herds. Ranchers here and in other states are also asking lawmakers to require developers and new homeowners in rural areas to fence their properties.

From California to Colorado, ranching interests also are taking the unusual step of joining forces with conservationists and creating trust funds to help preserve agricultural and grazing lands that are becoming prime targets for residential or commercial development.

"The demand exceeds our grasp already," said Steve Sinton, a California rancher who supervises a new land preservation trust for the state cattlemen's association. "This kind of livelihood is not easy to keep up anymore."

Dean Rhoads, a state senator and rancher in northern Nevada, is sponsoring several bills to help cattlemen, but he sounds startled by the pace of change.

"These 100-acre developments seem to be springing up almost overnight," Rhoads said. "It used to be in these parts that you had to watch out for the cattle. Now everyone expects the cattle to be looking out for you."

And it could get tougher. One hard truth is that the cowboys of today's West are simply getting older. In many western states, the average age of a rancher is now about 55 and climbing, a decade older than it was a generation ago.

As more ranchers retire with no one to take up their herds, they say they have no choice but to sell their family lands. In some surveys, about one-fourth of ranchers have said they may quit and sell if life on the range gets more difficult and frontier land values in the West keep rising.

Another problem is that grazing land is getting harder to find and afford. But some say that ranchers have only themselves to blame. Because the federal government owns so much land in the West--in Nevada, it has title to about 80 percent of the land--many ranchers rely on public space to raise their cattle.

But environmental groups have long complained that too many greedy ranchers are recklessly overgrazing the land and ruining wildlife habitats. They have been pressuring federal officials to raise grazing fees and limit access to some lands. Several lawsuits to protect endangered species have forced some ranchers around the West to fence their herds away from rivers and streams.

In Nevada and other western states, new suburbs also have begun to call the shots in politics, at times at the expense of rural interests that once had much more clout. Most members of Nevada's legislature, for example, now hail from metropolitan Las Vegas, and cattle are the least of their worries.

The trend is difficult for ranching groups to accept. Some suburban officials whose districts are expanding into the open range are even talking about forcing ranchers to fence their land for the first time for the sake of new residents.

"We've been here for four generations, from when a place like Las Vegas was only a mud hole," said Betsy Macfarlan, the executive director of the Nevada Cattlemen's Association. "Why should we have to conform to their standards?"

Washoe County, which is spread across the eastern slopes of the Sierra Nevada mountains, typifies the growth that many ranchers have begun to dread. Stoked by economic good fortune in Reno's casino and convention industry, the county's population has increased by nearly 30 percent this decade--from 254,000 to 324,000. And demographers anticipate the total to reach 400,000 over the next decade, which would no doubt push new development farther into the frontier.

A similar pattern is evident in other parts of rural Nevada, and already is a prime source of tension, both serious and comic.

Dennis Journigan, an inspector for the state agriculture department, said that violence or harassment against cattle is still quite uncommon, yet seems to be on the rise. What he says he sees most in his rounds across the state is confusion and frustration with all the change coming to the land.

A few weeks ago, he had to look into a case involving a homeowner who had been hospitalized with minor injuries after a cow that he tried to chase from his property ran him down. Journigan also said there have been a number of times when newcomers have complained to him about ranchers because cattle keep turning up on their property even though they have "No Trespassing" signs posted.

"I've had to say, 'Look, fella, the cows can't read,' " he said.

The Palomino Valley does not look like a suburb--yet. Its miles of meadows and streams are mostly unspoiled by development, but every year more homes are built and keep taming the range that ranchers such as Depaoli once knew.

He is trying to make the best of it, though. At 64, he is as lean as a nail and every bit western grit in a muddied cowboy hat and worn denim jacket. This is the land of his forefathers. Ranching has been in his family for generations. He still rides horseback under the vast western sky some days to tend to his herd, alone or with a cousin's husband--the only person around willing to help with the work. But Depaoli still wants to look on the bright side.

Some settlers are happy to fence their few acres of property for his sake, and others say they don't mind the sight of cattle at all because it lends old-West authenticity to the setting. "They like 'em as scenery," Depaoli said.

At other moments, all the new headaches hardly seem worth fighting. There was a time when Depaoli would run nearly 1,000 cattle across the wide-open valley. But his herd has dwindled to about 250 now, and no route is easy to navigate anymore. He also is not getting any younger.

Deep in the valley one recent day, Depaoli parked his creaking truck and set out on foot into the brush. He pointed to a natural spring, and knelt down to collect a few unusual shavings in his leathered hand--chipped arrowheads, from an era when tribes looked upon the first ranchers with the same dismay that modern cattlemen have for the affluent urban refugees coming their way now.

Then, as the shadows of the afternoon grew, Depaoli looked over to a mountain pass that he had led herds through many times. What he saw there was a three-story estate, a long driveway and several cars.

"It's all happening so fast," the old cowboy said, "but I'm not done out here yet."