At one point, the Chimakuan languages were most likely distributed throughout what is now Western Washington, before retreating to the Olympic Peninsula after the expansion of the Coast Salish people.

A 1877 report by George Gibbs claimed that he had been told that the Chimakuan people had at one point inhabited the upper portions of the Nisqually and Cowlitz Rivers.

It was spoken until the 1940s on the east side of the Olympic Peninsula between Port Townsend and Hood Canal.

During the late 20th and early 21st centuries a revitalization effort began, and it is today spoken as a second language by a relatively small amount of the Quileute tribe on the west coast of the Olympic Peninsula, south of Cape Flattery.

The Proto-Chimakuan sound system, as reconstructed by Powell,[2] contained three vowels, long and short, and lexical stress (accompanied by a higher pitch as in English).

The Proto-Chimakuan palato-alveolar fricative and affricates *š, *č, *č̓ developed as positional allophones of Pre-Proto-Chimakuan *xʷ, *kʷ, *k̓ʷ before the front vowel *i.

This is why the Quileute and Chemakum reflexes of Proto-Chimakuan *xʷ, *kʷ, *k̓ʷ and *š, *č, *č̓ are largely in complementary distribution, though they are clearly phonemized in the modern languages (and probably already was in Late Proto-Chimakuan before it split) owing to loans and some irregular and analogical developments, especially in Chemakum.

The vocalic system of Proto-Chimakuan is much harder to reconstruct as Boas' Chemakum data don't allow for an unambiguous reading of the phonemic vowels in that language.

However, assuming a Quileute-like 3-vowel system with an extra parameter of vowel length, Powel was able to reconstruct a similar provisional vocalic inventory for the proto-language: short *a, *e, *o, and long *a·, *e·, *o·.