A forum to discuss the sale of a 3,500-acre parcel of the former Marine Corps Air Station El Toro is planned for 10 a.m. on April 28. The site is the largest land sale in Orange County, Calif., in the past 30 years.

The property will be sold to developers through an online auction process that will begin this fall, and will be handled by the U.S. General Services Administration on behalf of the Department of Navy. The sale is expected to be completed by the end of the year.

After a decade of land-use battles, El Toro is slated for redevelopment as the nation’s second-largest municipal park. After the sale, the land reportedly will be annexed by the city of Irvine and will follow its land-use plans, which includes using part of the land as a public park. The city could raise nearly $200 million in developer fees and $153 million in property taxes from future owners inside the park’s boundaries.