The owners of Illinois’ highest-grossing casino are going all-in with a proposal to operate the newly authorized casino in Waukegan.

Churchill Downs Inc. and Rush Street Gaming announced Thursday they’re among the developers vying for the north suburban casino license that’s part of Illinois’ massive gambling expansion signed into law earlier this summer.

The gambling giants jointly own Rivers Casino in Des Plaines, which generated nearly $442 million last year, more than double any of the state’s nine other existing casinos.

Their proposed Rivers Casino Waukegan would be a 1,625-gaming position parlor at Waukegan’s Fountain Square, a former shopping mall at Lakehurst Road and Northpoint Boulevard.

They say their plan will create more than 1,200 permanent jobs and 900 construction jobs while pumping more than $150 million annually into the local economy.

“We’re happy to be considered to develop and operate what we know will be a leading entertainment destination for the City of Waukegan, Lake County and the State of Illinois,” Rush Street Gaming CEO Greg Carlin said in a statement.

Six groups have submitted proposals to the city, according to Waukegan officials, who say they’ll release a short list of finalists next week. The city will then recommend one or more of those finalists to the Illinois Gaming Board by Oct. 26. That state agency has the final say on issuing a license.

The Churchill Downs-Rush Street group is the fourth to announce they’re among the bidders. Others who have announced proposals include Potawatami Hotel & Casino, North Point Casino and Full House Resorts Inc.

Churchill Downs executives hinted earlier this month they’d jump in the race for one of Illinois’ six new casino licenses. In an Aug. 1 investors’ conference call, Churchill Downs CEO Bill Carstanjen said they planned to apply for a sports book at Rivers Des Plaines, as well as the 800 additional gaming positions allowed under the new gambling law, bringing their total to 2,000. He also said they’d apply for newly authorized gaming positions at Arlington International Racecourse, another Churchill Downs property.

Rush Street, founded by Carlin and Chicago billionaire Neil Bluhm, also operates casinos in New York, Pennsylvania and Canada. Churchill Downs has numerous gaming interests nationwide, including the namesake Louisville home of the Kentucky Derby.

The companies say a second Illinois Rivers Casino “creates a synergy in the market” that would attract gamblers throughout the region, “complementing — rather than cannibalizing — current local video gaming operators.”

Their Waukegan proposal also includes a sports book, poker room and Luxbar, an “upscale gastropub.”