Cynthia Irwin-Williams (April 14, 1936 – June 15, 1990) was an archaeologist of the prehistoric American Southwest.

Beginning her career in the 1950s, Irwin-Williams was considered a groundbreaker for women in archaeology, like her friend and supporter Hannah Marie Wormington.

[1] In 1966 Irwin-Williams and her brother published a book of her findings from the Magic Mountain site excavation performed for the Peabody Museum of Harvard University in 1959–1960.

It was named by Irwin-Williams for those areas: Pinto Basin (PI), Cochise tradition (CO) and San Jose (SA), which all together is "Picosa".

Irwin contended that the Ancient Pueblo People, or Anasazi, developed, at least in part, from the Oshara.

[8] She then moved to Eastern New Mexico University where she taught from 1964-1982, where she held the endowed Llano Estacado Distinguished Research Professorship from 1978 to 1982.

[8] Irwin-Williams moved to Reno, Nevada in 1982 to her new appointment as the executive director of the Social Science Center, Desert Research Institute, later achieving the position of Research Professor, Quaternary Science Center in 1988, which she held until her untimely death in 1990 at age 54.

After a long chronic illness, Irwin-Williams died on June 15, 1990, in Reno, Nevada.

Investigations at the Salmon Site: The Structure of Chacoan Society in the Northern Southwest.

Anasazi Puebloan Adaptation in Response to Climatic Stress: Prehistory of the Middle Rio Puerco Valley.