"Mono" or "Monache" is a Yokuts term of uncertain meaning. Also known as the Western Mono, they are Nimi, or "People," in their own language. Before contact with Europeans, the Monos lived in central California along the Sierra Nevada, higher in elevation (by 3,000 to 7,000 feet) than the Foothill Yokuts. Today most Monos live on Big Sandy and Cold Springs Rancherias, with other Indians on the Tule River Reservation, and in several northern California communities. The Mono population stood at roughly 2,500 in the late eighteenth century. Mono is a language of the western group of the Numic family of the Uto-Aztecan language stock.

During the eighteenth century, the Monos included six independent groups (Northfork Monos, Wobonuchs, Entimbichs, Michahays, Waksachis, and Patwishas). They were in general culturally similar to the neighboring Foothill Yokuts. Since they lived in a region not highly desired by miners or non-Native settlers, they enjoyed relatively higher survival rates in the nineteenth century than did most other California Indian peoples.

The Monos believed that spirits contained supernatural powers that might be employed by people with the proper knowledge. Supernatural powers were obtained through a connection with nature or by taking jimsonweed (datura), a drug, as part of a ritual. Although shamans were especially skilled in these techniques, most people thought it a good idea to possess some powers for general success in life. Shamans used their powers for curing. However, they could also hurt or kill, and various evil activities were often ascribed to them.

Ceremonies included bear dances (by members of the Bear lineage) and the annual mourning ceremony. The Monos brought the Ghost Dance of 1870 west of the Sierra Nevada. This phenomenon ended by 1875, largely because it failed to bring back the dead as promised; the 1890 Ghost Dance revival had no impact on the Monos.

Each Mono group was composed of villages or hamlets of between one and eight huts, each led by a (usually hereditary male) chief. Patrilineal lineages, such as Eagle, Dove, Roadrunner, and Bear, were social organizations. The chief (from the Eagle lineage) arranged ceremonies, saw to the needy, and sanctioned the killing of evil shamans or others. He led by suggestion rather than by command. A messenger (Roadrunner lineage) assisted the chief and settled quarrels. They both had a symbol of office, an eight-foot-long cane with red-painted bands and string on top. Only the Northfork Monos had formal intradivision groups (Eagle and Dove), each with its own chief.

The Monos built three types of houses: conical with an excavated floor, oval with a ridgepole, and conical with a center pole covered by thatch or cedar bark. Houses were arranged in a semicircle around the village. Most villages also contained a sweat house (male only), an acorn storehouse, and an open area used for dances and ceremonies.

Acorns were the staple food of these hunter-gatherers. They also ate roots, pine nuts, seeds, and berries (and drank cider from manzanita berries). They hunted and trapped deer, bear, rabbits, and squirrels. Good hunters shared their meat. Bears were often killed by blocking egress from their caves and then shooting them. Fish were caught with traps, weirs, nets, and spears.

As "homeless Indians," the Monos received three rancherias from the federal government in the 1910s. Some individuals also acquired parcels of land. Many people retained their traditional subsistence gathering patterns while working as loggers, ranch hands, miners, and domestic help. As was the case with many other Indians, a large number of Monos moved to the cities after World War II.