The Vinkus, also 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 a vast expanse of grasslands in the western portion of Oz separated from the rest of the country by the semi-impassible mountain range known as the Great Kells and accessible only at certain times of year through Kumbricia's Pass. The northern, southern, and western borders of The Vinkus are edged by desert.
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, and Yunamata 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 until Rain Thropp, the illegitimate granddaughter of Fiyero Tigelaar and Elphaba Thropp took up the mantle as princess.
The books suggests that Winkies speak a different language than the rest of Oz and that they learn Ozian to communicate with people outside the Vinkus.
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 the 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.
- 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.
- Sarima's Sisters: Midwives and servants of the Dowager Princess.
- Elphaba Thropp: Lived with the family for 7 years and became the Wicked Witch of the West during her stay there.
- Liir Thropp: Lived with the family for 7 years and is the illegitimate son of Elphaba and Fiyero.
- Oziandra "Rain" Thropp: Daughter of Liir and the newly appointed Princess of the Arjikis.
- 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.
- The Yunamata / A nomadic tribe located in the Thousand Year Grasslands. They speak in a foreign tongue and are cavorting and opinionated in personality. Members of the tribe have long lashes, narrow elbows, supple wrists, and thin concentrated lips. Elphaba Thropp sees similarities between the tribe and the Quadlings and assumes they are distant cousins.