Pretty much the entire county is scenic, with stunning sights to be observed along the coast, and in the mountain ranges. Mount Errigal, is a quartzite-topped mountain is in the Derryveagh mountains to the north of the county, with the Bluestack mountains to the south.
The Slieve League cliffs in the county are among the highest sea cliffs in Europe. Ireland's most northerly point, at Malin Head, is in the county.
A preserved railway (http://homepage.tinet.ie/...), with an operative original railcar open for public journeys, is located at Fintown in the centre of the county; when restoration is complete this will link to Glenties in the west of the county. In addition, a separate museum (http://www.cdrrl.com) for a separate part of Donegal's now-gone but formerly extensive narrow gauge railway network is in Donegal Town, located in the towns former station house.
An operative corn and flax mill (http://www.heritageirelan...) is preserved at Newmills, outside Letterkenny, with the county museum (http://www.donegal.ie/dcc...) being located in the towns former workhouse. Another former workhouse, at Dunfanaghy, has been partially restored as workhouse museum.
The county's two main offshore islands are both still inhabited, and both worth a visit. In addition, some of the smaller islands are worth seeing, if you have the means to get to them. Most of these are uninhabited during the winter and lack power, water, or any other means of life for anybody but temporary visitors.
Arranmore (http://www.arainnmhor.com/), the larger and closer inland of the two, has two hotels, 7 pubs, some watersports activities and mountain trails for hikers; and is accessible by a regular, multiple times daily car ferry service. A pre-Christian hill fort as well as ruins of a coastguard station, 1700's lighthouse and World War Two lookout post are all visible on the island. The country's only off-shore football team is based here, with a pitch built on sand dunes on the south of the island.
Tory Island (http://www.toryhotel.com/), is smaller, less populous, and further offshore, and is accessible only by a passenger-only ferry; which runs multiple times daily during the summer, dropping to 5 times a week in winter. The island has a 14-bedroom hotel. Tory's history is lived out to this very day with an elected "king" who attempts to greet all tourists, and a round tower with famed "cursing stones" and Celtic cross.