The 200-room hotel under construction at Graton Resort & Casino since September will officially open to the public on Nov. 15, and casino officials said they’ve already taken hundreds of reservations.

“We took the first one about a month ago,” said Joe Hasson, Graton Resort & Casino’s vice president and general manager.

The $175 million hotel is set on the south side of the casino outside Rohnert Park and will feature a 10,000-square-foot spa, a fitness center, a 20,000-square-foot event space and an expansive outdoor pool. The guest rooms will range in size from 500 square feet to 2,600 square feet, according to Hasson. Weekday room rates start at $399; weekend rates at $499.

It will be the fourth-largest hotel in Sonoma County, behind the Hilton Sonoma Wine Country in Santa Rosa, the Doubletree by Hilton in Rohnert Park and the Fairmont Sonoma Mission Inn & Spa in Sonoma.

Since it opened in 2013, the casino, owned by the Federated Indians of Graton Rancheria and operated by Station Casinos of Las Vegas, has partnered with local hotels for lodging for its guests.

With the gaming destination’s expansion comes the need for a larger workforce. A job fair will be held Saturday from 10 a.m. to 1 p.m. at The Event, a conference area within the casino. Management is looking to fill 300 jobs both in the casino and in the newly opening hotel, some with immediate start dates and some not until November, Hasson said.

It is the biggest single-business job fair Sonoma County has seen for a long time, said Heather LoBue, program manager for the Sonoma County Economic Development Board, noting that only job fairs at Target and Walmart rivaled it in size.

Ben Stone, executive director of the board, said Graton Resort & Casino might actually have a tough time filling all those jobs.

“Our unemployment rate is so low that the challenge will be for the casino to find 300 people to hire, given how tight things are,” he said. “It’s just coming at a time when there’s been a lot of other hiring.”

Available jobs will include everything from traditional hotel positions in front office, concierge and housekeeping, to work at the hotel’s spa “and everything in between,” Hasson said.

With the expansion, and the expected proportional rise in traffic inside the casino, hiring will also include dealers, slot machine attendants, cooks, engineers and security officers.

“All the things that make a business of this size go,” he said.

You can reach Staff Writer Christi Warren at 707-521-5205 or christi.warren@pressdemocrat.com. On Twitter @SeaWarren.