The Plomosa Mountains are a mountain range in La Paz County, Arizona, running generally south of Bouse, Arizona near the Arizona/California border.

Quartzsite lies to the west across the La Posa Plain.

The New Water Mountains lie to the southeast beyond Black Mesa.

The Plomosa ghost town and mining camp lie on the southwest side of the range.

[4] The highpoint of the range is Black Mesa (La Paz County) in the southern regions.