CHARLESTON, S.C. — Charleston Mayor Joe Riley and Medical University of South Carolina President Ray Greenberg have announced plans for a $1 billion, 20-year development on the Charleston peninsula.

Riley told reporters Monday the project could be the largest in the city’s history.

Officials say the Horizon District between the city’s medical complex and The Citadel along the Ashley River will be developed for housing, stores and research and technology businesses.

Half of the 20 acres on the site are half owned by the city and half by MUSC. It is now largely open space used for parking for the university. Much of the development would be done by private companies.

Officials are sending requests for proposals for a master developer and say the first buildings could be up in a few years.