North Ronaldsay is the northernmost of the Orkney Islands, Scotland and with an area of 2.7 square miles (7.0 km²) is the fourteenth largest.

North Ronaldsay lies around 4 kilometres (2.5 mi) north of its nearest neighbour, Sanday at grid reference HY759542. The island is around 5 kilometres (3.1 mi) long along its length and is defined by two large sandy bays; Linklet Bay on the eastern shoreline and South Bay at the south. The west of the island is very rocky with many skerries. Low lying and exposed, the island's climate is extremely changeable and frequently inclement. The surrounding waters are stormy and treacherous, and have been a notorious 'graveyard' for ships (hence the unusually early provision of a lighthouse on the island).

Hollandstoun at the south of the island is the most sizable settlement lying roughly equidistant from the airfield and the pier. The island is also home to a bird observatory.

North Ronaldsay has a unique dry stane dyke that surrounds the island whose purpose is to keep the seaweed-eating North Ronaldsay sheep off the arable land.

The Sheep is a character, created by Charles Lutwidge Dodgson, aka Lewis Carroll. It appeared in Dodgson's book, Through the Looking-Glass, the sequel to his book Alice's Adventures in Wonderland.

The Sheep is first mentioned in the fifth chapter of Through the Looking-Glass, "Wool and Water". The White Queen is talking to Alice, when she suddenly starts "baa-ing" and then seems to 'wrap herself in wool'. Alice figures out she is in a shop, and that The White Queen has turned into a sheep. The Sheep sits in her chair knitting as Alice looks around the shop. She gives Alice a pair of her knitting needles, and asks her if she can row. As Alice begins to answer, she realizes that they are in a little boat, and that the needles have turned into oars. As they glide along the water, the Sheep repeatedly shouts out "Feather," and tells Alice that they will be catching crabs. Alice's attention is then put onto some scented rushes growing in the water. She tries picking them, but they are only 'dream rushes' and melt away. She then quickly catches a crab, which she actually didn't see, and they are all suddenly in the shop again. Alice buys an egg from the Sheep (that ends up turning into Humpty Dumpty) and the two part ways.