Open 365 days of the year, Mount Vernon is the most popular historic estate in America. Over 85 million people have visited Mount Vernon since 1860, when the estate officially opened to the public. The estate, gardens, and farm of Mount Vernon totaled some 8,000 acres in the 18th century. Presently, an estimated 500 acres of this historic property have been painstakingly preserved along the banks of the Potomac River. Visiting choirs are welcome to perform informally on the estate grounds. Washington D.C.