With a glistening $400 million casino set to open in downtown Cincinnati on Monday, officials and casino executives in two neighboring states are looking at the development with trepidation as they prepare to watch tax dollars flow into Ohio.

Horseshoe Casino Cincinnati is all but guaranteed to dip into Indiana's casino revenues, which have steadily declined in the past few years. For Kentucky, Cincinnati's casino represents money that it could be, but isn't, making.

The casino will open Monday night after more than two years of construction. It will be the last of four casinos that Ohio voters approved in 2009 after a statewide campaign touted the immediate boost the casinos would give to Ohio's economy.

Casinos in Cleveland, Toledo and Columbus all opened over the past year and have brought in nearly $404 million combined. From that, about $133.2 million has gone to Ohio schools, counties and cities.

Cincinnati's casino is projected to draw about $227 million in gross revenue in its first year. That would bring in about $75 million in taxes.

Though those figures are far lower than earlier estimates, Cincinnati Mayor Mark Mallory hailed the casino as a regional and national destination ahead of its opening.

"It's a home run," Mallory said. "This casino will have the ability to draw people from all around the country. ... This is a top-line casino, and the people who are accustomed to the big casinos in Vegas, they're not going to miss anything here."

Though no hotels are attached, and nothing quite compares to the energy or spectacle of the Vegas strip, Mallory referred to the Cincinnati casino's bustling location on what used to be a run-down parking lot and ticked off amenities including a buffet, a VIP players' lounge with high limits, a World Series of Poker room and three outward-facing restaurants, including Jimmy Buffet's Margaritaville and Bobby's Burger Palace by celebrity chef Bobby Flay. Both Buffett and Flay also have outposts in Las Vegas.

Across the state line in Indiana, casinos and state leaders have been bracing for the development.

"The hovering threat to Indiana's dominance in commercial casino revenues among its sister states is evolving into reality," Ernest Yelton, executive director of Indiana's Gaming Commission, wrote in a 2012 annual report to Gov. Mitch Daniels. Nearly all of Indiana's 13 gambling venues would be affected, he added, "some dearly."

Over the past two decades, Indiana's casino industry has brought in $10 billion in taxes to become the state's third-largest revenue source after sales and income taxes.

But casinos there are in decline. Last year, taxes on casino revenues in Indiana dropped 4.2 percent, from $787.4 million in 2011 to $754 million in 2012, the steepest drop amid a three-year fall.

In the annual report, Yelton cited the economic climate, pointed to threats to Indiana's industry from several neighboring states, including Michigan and Kentucky, and called Ohio's new casinos the biggest challenge facing Indiana.

In Kentucky, Democratic Gov. Steve Beshear has tried and failed every year since his 2007 election to legalize casinos in the face of opposition from Republican lawmakers and a racetrack industry worried about competition.

At a news conference Feb. 21, Beshear lamented the opening of Cincinnati's casino.

"The casino in Cincinnati's good news for Ohio and bad news for Kentucky," Beshear said. "Right now we've got thousands of Kentuckians that have been going out of state, and now they'll also be going to Cincinnati to spend their Kentucky money in Ohio, and then Ohio's going to keep the benefits of that."

Beshear said that Kentucky needs to legalize casinos to start bringing in taxes for schools and infrastructure.

"I hope that sooner or later we get our act together here and legalize casino gaming so that we can start keeping our money at home," he said.

Ohio had a similar battle before voters approved the state's four casinos in 2009, with four previous failed attempts.

The 2009 issue won approval after proponents lamented tax dollars going to Indiana, Michigan and West Virginia, and said that casinos in Ohio's four largest cities would create tens of thousands of jobs and boost the economy.

Opponents of Ohio's casinos largely consisted of groups that criticized revenue predictions as inflated and pointed to the societal ills of gambling, including addictions that leave some destitute. They also criticized Ohio's 33-percent tax rate on the casinos for being lower than some other states.

Ohio's casinos were original forecast to bring in nearly $2 billion annually. That would have generated $643 million in taxes for schools, counties and cities. Now, their yearly revenues are now expected to be just under $1 billion.

Industry experts say the lower revenues are a result of the economic climate and competition from storefront gambling-style operations in the state known as Internet cafes.