Gillikin Country is the only region in Oz that is not mentioned by name in the first book, The Wonderful Wizard of Oz. L. Frank Baum first used the name "Gillikin" at the beginning of the second book, The Marvelous Land of Oz. In her books, Ruth Plumly Thompson generally spells the country's name "Gilliken."
The dominant color of Gillikin Country is purple, and its people are occasionally described as wearing purple clothes and even sometimes having purple hair. Of the four quadrants of Oz, Gillikin is known as the wildest and least explored, home to vast forests and mountains.
Like all of the countries of Oz, the Gillikin Country contains various unusual sights and places. Among them are:
- The forest of the Winged Monkeys, creatures that obey whoever wears the enchanted Golden Cap
- The palace of the Good Witch of the North
- The house and farm of Mombi, the former Wicked Witch of the North, who kidnapped Ozma's grandfather. The Wizard payed Mombi to keep Ozma and her father prisoner while he ruled the land of Oz.
- The village of Loonville, whose balloon-like inhabitants warn strangers to stay away from their clearing (the Loons can also become too puffed-up)
- The Rolling Lands, an area of vast hills and valleys
- The castle of Mrs. Yoop
- Dragons living beneath the earth's surface, allowed to come out once every 100 years in search of food
- The Magic Isle and nearby diamond palace of the Lonesome Duck
- The Forest of Gugu
- Giant purple spiders that catch travelers in their webs and make them their servants
- Mist Maidens, fairies who live in a fog bank
- Flatheads, people living on a mountaintop whose heads are flat and carried their brains in a can in their pockets
- Skeezers, once friends and now rivals of the Flatheads who live within a glass city in the middle of a lake
- Reera the Red, a witch preferring her privacy who specializes in transformations
- Pumperdink, an elaborate fairy tale kingdom that is known for dipping it's criminals in ink.
- Up Town, proclaimed the capital of the Gillikin Country after the Good Witch of the North abandoned her post. It is inhabited by the Uplanders.
- Bookville, a town of animated books.
- Icetown, a frozen town.
- Regalia, the sister city of Pumperdink.
- Upandup Mountain
- Terp the Terrible's Castle
- The village of the Lanternesians
- Dinker's Shop of Smokables
- Candy County
- The Equinots
- The Hoopers
- The Scooters
- An unidentified jungle where the Leopard with the Changeable Spots lives
In Gregory Maguire's revisionist Oz novels Wicked: The Life and Times of the Wicked Witch of the West and Son of a Witch, the Gillikin country is portrayed as more prosperous and industrially developed than other regions of Oz, and home of Shiz University. There is a railway (Great Gillikin Railway) that connects most of the Gillikin towns and connects to the yellow brick road at the location of Shiz. Galinda hails from Gillikin, as do (according to some) the ruling Ozma family. Gillikinese people are distinguishable by their prominent foreheads and slightly gapped front teeth. They often have heads of curling blond hair, and are believed to be temperamental by non-Gillikinese.