Greencastle or Green Castle may refer to: Places Germany Green Castle (Grünes Schloss), Weimar; see Duchess Anna Amalia Library Ireland Greencastle, County Donegal, Republic of Ireland Greencastle, County Down, Northern Ireland Greencastle, County Tyrone, Northern Ireland Scotland Green Castle, Portknockie, an Iron Age and Pictish promontory fort United States Greencastle, Indiana, a city Greencastle, Missouri, a city Greencastle, Pennsylvania, a borough Greencastle, West Virginia, an unincorporated community Greencastle, Kanawha County, West Virginia, an unincorporated community Other uses Greencastle (film)