Glenveagh Castle is located about 25km northwest of Letterkenny. It is situated within Glenveagh National Park, and it is quite the popular attraction to visit for tourists in the area. There is also a garden by the castle, and the park itself has many walking trails filled with stunning scenery of the lake, mountains, and the countryside. Make sure to bring your walking shoes though since the walk from the car park to the castle and gardens is about 4km long.