Mountrail County Sheriff Ken Halvorson can easily spot drivers from outside the area, and not just by their out-of-state plates.

"A lot of the older vehicles are the locals," Halvorson said.

Oil has brought economic prosperity and people to Mountrail County in northwestern North Dakota, one of the hottest areas in the state's booming oil patch. Traffic has increased significantly and crime has spiked some, keeping the handful of deputies busy in the county that was pegged at 6,600 residents in the 2000 Census, Halvorson said.

"We've jumped a couple of thousand since then," he said.

Oil companies are stepping in to help the sheriff, who worked as a roughneck in North Dakota's last oil boom in the 1970s.

Halvorson said some larger oil companies in the area gave the county a $200,000 grant this year to boost law enforcement. The money is being used to hire two deputies, bringing the number to eight, and to purchase more patrol cars and equipment for the new officers, he said.

"We're seeing more traffic violations because there is much more traffic," Halvorson said. "We're finding a lot of out-of-state people are wanted in another state, so some are bringing their baggage with them."

The warrants are mostly civil matters, the sheriff said. Major crimes still are a rarity, he said, thanks in part to mandatory drug testing by most oil companies.

Ron Ness, president of the North Dakota Petroleum Council, said oil companies routinely give grants to communities, but he believes it's the first time in North Dakota that money has been earmarked specifically for law enforcement.

"It likely does happen in other areas of the U.S., but it's the first time to my knowledge it's been done in the state," said Ness, whose group represents about 160 companies. "We saw a need and we were able to assist."

Still, Mountrail County has only one deputy for every 250 square miles.

"We earn our money here," the sheriff said.

"Mountrail County is very unique," Ness said. "The activity up there is very heavy and the wells have been very productive - it absolutely is the hottest area in the oil patch."

The oil money given to the county to boost law enforcement was done quietly - by design, Ness said.

"We don't want that expectation placed on every company - every well is different and every company's economics are different," he said.

Stanley Mayor Mike Hynek said there is less mischief in the area than in the boom days of the 1970s and early 1980s, even with more people now.

He estimated the population of Stanley, the county seat, at about 1,800, or about 500 more than the census taken eight years ago.

"Things have gone pretty smooth with the tremendous amount of people here now," Hynek said. "They all seem to be pretty well-behaved."

Hynek also said drug testing by the oil companies has helped.

The city had three police officers. One recently moved to Williston because his wife got an oil-industry job there, Hynek said.

Crime is down on the list of city problems, Hynek said. Housing, he said, is the biggest issue.

"We've got not a place to rent or a house to buy," the mayor said. "We're busting at the seams."

Many oil field workers commute from Minot, which is about an hour's drive away. Hynek said the city has annexed some land recently for housing development, though nothing is being built.

Still, he said, oil has been positive in the town, where American flags line Main Street year round, and country music is piped through downtown by the local hardware store.

Sales tax revenue for the city has jumped about 150 percent in the past year, which will help with water, sewer and road improvements, and other projects, such as storefront makeovers for businesses, the mayor said.

"There's more jingle in everybody's pocket around here," Hynek said.

The jingle is felt in everything from pizza sales to piano lessons.

Jeff Schaefer, general manager of Farmers Union Oil Co., said the co-op's gas station and convenience store has seen sales skyrocket in the past year. Pizzas that warm under heat lamps are on pace to set a record $1 million in sales this year. Sales of pop and candy also should top $1 million this year, he said.

Pop, pizza and candy sales are double what they were last year, and most are sold to oil-field workers, Schaefer said.

Petroleum sales also have doubled this year, to about $15 million, he said. Most of the fuel sold is diesel for trucks that support the oil industry.

Even piano lessons are in higher demand in Stanley.

"I have seen a spike in my waiting list," said Heide Fluhrer, a piano teacher who has about two dozen students. "I did take on a couple more, but I can only take so many."

Stanley barber Jacque Wing said business this year has been the best of his 40 years of haircutting.

"These people make a lot of money and they spend a lot of money," Wing said. "But at my shop, you can still get a $14 haircut for $10."

The town's drug store, famous for its Whirla Whip ice cream treat, has seen a big boost in business, said Suzie Trana, who works there.

The Whirla Whip, which comes in dozens of concoctions, has seen a tremendous uptick in sales, in all but the dill pickle-flavored blend, she said.

Mayor Hynek said the pickle-flavored ice cream may be the only thing that hasn't seen an increase in sales in Stanley.

"I think it may be because we don't have a lot of pregnant women in town," he said.