Euphagus cyanocephalus, commonly known as the Brewer's Blackbird, is native to much of North America. Its range includes parts of Canada, the United States, and northern Mexico. It is most commonly found in the western and central regions of the United States, extending into southern Canada and parts of northern Mexico.

The Brewer's Blackbird typically inhabits open and semi-open landscapes. It is frequently found in environments such as grasslands, farmland, city parks, gardens, coastal regions, and areas with sparse trees or shrubs. The species favors habitats that offer abundant food resources and adequate nesting sites. In the more arid regions, such as the southwestern United States, it may be found near water sources.

Brewer's Blackbird is an opportunistic feeder, primarily consuming seeds, grains, and insects. Its ecological role includes seed dispersal and insect population control. It is well-adapted to human-altered environments and can thrive in urban and suburban settings. The species shows adaptability to various climates, from the temperate zones of Canada to the desert regions of the United States, demonstrating versatility in habitat utilization.