The Vinkus, often mistakenly called the Winkie Country, is the western quadrant of the land of Oz. The inhabitants of this land are called Winkies. While not having an overall leader, the land is split into different tribes, each ruled by a respective chieftain.
The Vinkus is the largest of the four provinces, extending totally from south to north and standing on western Oz, this region is also almost completely isolated from the rest of the country, as it is bordered by deserts at north, west and south, and obstructed to the east by the Great and Lesser Kells mountains, being the only way in the Kumbricia's Pass, opened at certain times of the year, The Vinkus is the less populated and fertile land as well, being portrayed as a semi-desolated place with vast extenses of grasslands, mountains and deserts, there is only a poisonous lake, Kellswater, with oakhair forest, an oasis, by its side, the Vinkus River runs up to Kiamo Ko, the fortress home of the Tigelaar Family, leaders of the Arjiki Tribe and one of the only permanent settlements in the region. There are other places mentioned as well, such as Nether How, a group of diminutive lakes, Applepress Farm, an abandoned warehouse formerly used by the maunts of the Cloister of Saint Glinda, The Thursk Desert, The Sour Sands, The Thousand Year Grasslands, Ugabu, disputed land in northern Vinkus, and Kvon Altar, a strange place that is used as a sacred sanctuary by the isolated clan of Draffe people, a dark occultist people who are said to worship death. It is rumored that there are many underground water springs in the Vinkus.
The way that the Vinkus is described is similar to the terrain and landscape of the American Great Plains and the Middle Eastern grasslands.
The Vinkus is inhabited by Winkies, primarily made up of nomadic pastoralists such as the Arjiki, Scrow, Yunamata, and Ugubezi tribes. Some groups, such as the Scrow and Yunamata are at odds with one another. From the novel, it seems that the semi-sedentary Arjiki tribe is the largest and most powerful in all the Vinkus, as the tribe has many villages and the mountain fortress of Kiamo Ko, the home of their rulers, the Tigelaar family. Though the family was wiped out by the Wizard's attempt to rein in the Vinkus, the political position of the Arjiki seems to have declined considerably.
Most Winkies speak a different language than the rest of Oz and that they learn Ozian to communicate with people outside the Vinkus. For example, the language of the Yunamata is Yumish.
With their physical descriptions, the prejudice impososed on them, and the way their behaviour and cultures are described, the inhabitants of the Vinkus are reminiscent of Romani gypsies, Middle Easterners, or Native Americans.
- The Arjiki / A large, powerful and advanced semi-sedentary tribe situated around Kiamo Ko, a fortress resting atop Knobblehead Pike in the Great Kells. Aside from Kiamo Ko, the tribe also has many village settlements scattered around the fortress including Fanarra, Upper Fanarra, Pumpernickel Rock, and Red Windmill. The tribe is a chieftain monarchy ruled by the Tigelaar family. Lurlinemas is celebrated among the tribe during the winter and in the summer they have a huge bonfire and slaughter pigs before the men descend into the plains for hunting. The tribe however, doesn't have much contact with the rest of Oz and don't hear the latest news unless a traveler or trader visits Kiamo Ko to inform the Tigelaar family. Members of the Arjiki tribe are ochre-skinned, and are painted with blue markings. The Arjiki typically are either nomads or shepherds who round-up sheep from the western foothills of the Great Kells. The Arjikis speak a language that shares grammar with Ozish, the common language in Oz.
- Marillot Tigellar: Former Chieftain of the Arjikis and the father of Fiyero.
- Baxiana of Upper Fanarra: Wife of Marillot and the mother of Fiyero.
- Fiyero Tigelaar: The Crowned Prince and later Chieftain of the Arjikis, succeeding his father.
- Sarima Tigelaar: Widowed wife of Fiyero and the Dowager Princess of the Arjikis.
- Irji Tigelaar: Eldest son of Fiyero and Sarima.
- Manek Tigelaar: Middle child of Fiyero and Sarima.
- Nor Tigelaar: Youngest child and daughter of Fiyero and Sarima who would later go by "Illianora".
- Sarima's Sisters: Midwives and servants of the Dowager Princess.
- Elphaba Thropp: Lived with the family and became the Wicked Witch of the West during her stay there.
- Liir Thropp: Lived with the family and is the illegitimate son of Elphaba and Fiyero.
- Oziandra "Rain" Thropp: Daughter of Liir and the official owner of Kiamo Ko.
- The Scrow / A nomadic tribe that wanders the Thousand Year Grasslands. They live in sand colored tents arranged in concentric circles with the princesses tent in the center. Members of the Scrow have poached salmon colored skin, protruding eyes, handsome noses, big buttocks, and wide rolling hips. The tribe also resorts to human sacrifices in their rituals. Members of the Scrow speak a language simply referred to as Scrow.
- Nastoya: An elephant disguised in the form of a human and former Princess of the Scrow.
- Shem Ottokos: A lord as well as Nastoya's chief translator/major domo, and later Chieftain after her death.
- Agroya: A trapper and thief who was kicked out of the tribe, he would later help out and, ultimately, ransack Liir and Candle at Nether How.
- The Yunamata / A nomadic tribe located in the Thousand Year Grasslands. They speak in a foreign tongue called Yumish and are cavorting and opinionated in personality. Members of the tribe have leathery skin, long lashes, narrow limbs, supple wrists, and thin concentrated lips that seemed party withdrawn into their mouths. Elphaba Thropp sees similarities between the tribe and the Quadlings and assumes they are distant cousins.
- The Ugubezi / A mentioned tribe of the Vinkus. Nothing is known of this tribe other than that they presumably live in Ugabu, disputed land in northern Vinkus.
- The Draffe / An isolated clan of people who live at Kvon Altar in the arid southwest of The Vinkus.