LOS ANGELES — Wearing a cowboy hat and leather jacket, a Las Vegas sheriff steps out of a diner and strolls down the street in front of the Golden Nugget casino, with its giant pineapple-shaped nugget encircled in neon lights.

He stops to greet his partner, who is clutching a copy of the Las Vegas Examiner when suddenly he notices some suspicious activity. The lawman grabs a broom handle and crosses the street to apprehend a gangster attempting to rob a jewelry store. But, what happens in Las Vegas doesn’t always stay in Vegas.

The scene, which will appear in the first episode of the new fall CBS drama “Vegas,” is not being filmed in Nevada’s Sin City but some 225 miles away at Santa Clarita Studios in northern Los Angeles County. There, workers built a replica of the original 1960s Vegas Strip, including a full-size casino, jail and sheriff’s station, for a cost of about $1.8 million. The set is unusually elaborate, especially for a network TV show.

The series, which stars Dennis Quaid as Sheriff Ralph Lamb — a fourth-generation rancher charged with bringing order to Las Vegas in the 1960s — also stands out because it is one of only a handful of new network dramas filming in Los Angeles this season. Most are filming in Canada, New York, Georgia and other locales that offer stronger tax incentives to producers than what is available in California.

“The trend in the last five years has been to take all of these shows out of town, so it’s a big deal to bring a high-profile show back to Los Angeles,” said Carey Meyer, production designer for “Vegas,” which debuts Sept. 25.

L.A. was no ace in the hole, however. The pilot for “Vegas” was shot in Albuquerque, Santa Fe and another Las Vegas — in New Mexico — to take advantage of that state’s tax credit.

And “Vegas” was not eligible to receive a 20 percent California film tax break because the credits target basic cable shows or prime-time series relocated from elsewhere.

Nonetheless, producers opted to film in Los Angeles County to take advantage of strong crews and because it was the preference of the stars, Quaid and Michael Chiklis, who plays Vincent Savino, a ruthless Chicago mobster and casino owner who wants to take over Las Vegas.

Quaid, the veteran actor who has starred in such movies as “Soul Surfer,” “The Day After Tomorrow” and “The Rookie,” said he was happy to stay close to his home in Los Angeles so he could see his twin children at night.

“I like sleeping in my own bed,” Quaid said during a break in filming this week.

Quaid, who owns a ranch in Montana, said he was instantly drawn to Lamb’s character and the concept behind “Vegas.”

“It’s like cowboys vs. gangsters,” he said. “How often do you get to see that?”