Pima County has reached a lease agreement with a group that wants to build a multimillion-dollar auto racecourse next to the Pima County Fairgrounds.

The Board of Supervisors approved an agreement Tuesday with Southern Arizona Raceway LLC to build the course on 400 acres south of the fairgrounds.

The developer will be required to spend at least $15 million to build a racetrack, lighting, pit road and pit area, and meet any other requirements mandated to qualify for a French-based Fédération Internationale de l’Automobile Grade 2 license. Southern Arizona Raceway also must provide amenities such as grandstands, rest-rooms and concessions in exchange for a long-term lease with the county.

The agreement also includes the group building the Arizona International MotorSports Museum, which the company hopes will rival the Pima Air and Space Museum.

Rent will be about $137,000 a year or 2 percent of gross revenues, whichever is greater.

The raceway will feature a lighted 2.8-mile course with 14 turns.

The developer will have up to 18 months to design and begin construction, and to line up investors, county documents say. The track is expected to open no later than spring 2017.