Castle Howard by Hawksmoor. The grounds of Castle Howard are also used as part of at least two charity running races during the year. Located on the Estate, but operating separately to the house and gardens and run by an entirely independent charitable trust, is the Yorkshire Arboretum. Originally created through the enthusiasm and partnership of George Howard (Lord Howard of Henderskelfe) and James Russell, over a period of eighteen years, from 1975 to 1992, it was opened to the public for the first time in 1999 and a new Visitor Centre opened in 2006.The arboretum's extensive and important collection of 6,000
Howard County, Maryland Baltimore's Washington Monument was later erected and the neighborhood of Mount Vernon was developed in the 1820s. The lands of prehistoric Howard County were populated by Native Americans. The Maryland Historical Trust has documented sites along the Patapsco, Patuxent, Middle and Little Patuxent River valleys. In 1652, the Susquehannock tribes signed a peace treaty with Maryland, giving up their provenance over the territory that is now Howard County. In 1800, the mean center of U.S. population as calculated by the US Census Bureau was found in what is now Howard County. In 1838, Dr. William Watkins of Richland Manor proposed