The Mayacmas Mountains are located south of the Mendocino Range, west of Clear Lake, and east of Ukiah in Mendocino and Lake Counties, and extend south into Napa and Sonoma Counties. The range stretches for 52 mi in a northwest-southeasterly direction.

The present spelling is used in the Statutes of 1850 (pp. 60 f.). The Geographic Board (Fifth Report) decided for Miyakma, but in 1941 it reversed this decision in favor of Mayacmas