Hizzoner is in contract to buy Ballyshear, a $20 million, eleven-bedroom Georgian mansion on 35 acres on Long Island’s Gold Coast, overlooking the National Golf Links of America. Built in 1910, the house has riding stables, a tennis court, and a pool. And, fittingly for the mayor of the city that enjoys Central Park as its front lawn, the gardens at Bloomberg’s new summer place were designed by Frederick Law Olmstead. [NYP]