The Plains and Sierra Miwok (the Miwok of the Sacramento Valley and the Sierra Mountains), were the largest group of Miwok

Miwok

Miwok can refer to any one of four linguistically related groups of Native Americans, native to Northern California, who spoke one of the Miwokan languages in the Utian family...

 Native American

Native Americans in the United States

Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...

 people. They lived in Northern California

Northern California

Northern California is the northern portion of the U.S. state of California. The San Francisco Bay Area , and Sacramento as well as its metropolitan area are the main population centers...

 on the western slope of the Sierra Nevada Mountains between the Fresno

Fresno River

The Fresno River is a river in Central California and a major tributary of the San Joaquin River. It runs approximately from the Sierra Nevada Range to the San Joaquin River.-Course:...

 and Cosumnes River

Cosumnes River

The Cosumnes River is a river in northern California in the United States. It rises on the western slope of the Sierra Nevada and flows approximately into the Central Valley, emptying into the Mokelumne River in the Sacramento-San Joaquin Delta.-Name:...

s and also in the "Central Valley" in the north portion of the Delta area, where the Cosumnes, Mokelumne, and Sacramento

Sacramento River

The Sacramento River is an important watercourse of Northern and Central California in the United States. The largest river in California, it rises on the eastern slopes of the Klamath Mountains, and after a journey south of over , empties into Suisun Bay, an arm of the San Francisco Bay, and...

 rivers converge.
The Plains and Sierra Miwok lived by hunting and gathering

Hunter-gatherer

A hunter-gatherer or forage society is one in which most or all food is obtained from wild plants and animals, in contrast to agricultural societies which rely mainly on domesticated species. Hunting and gathering was the ancestral subsistence mode of Homo, and all modern humans were...

, and lived in small local tribes, without centralized political authority.