Indigenous people used controlled burns at the site [Mime Prarie] to maintain the landscape as a prairie, allowing vegetation used for food or medicine to prosper.
There are approximately 8-10 mounds per acre, measuring 1–7 feet (0.30–2.13 m) in height and having diameters 7–40 feet (2.1–12.2 m).
The mounds were once part of a larger stretch of a prairie ecosystem encompassing approximately 180,000 acres (73,000 ha), spanning from present-day Joint Base Lewis–McChord through Chehalis and into Oakville.
The mounds, also described as hillocks, are situated on a plain of underlying cobble that is most likely a remnant of a glacial lake.
The origins of the word, mima (MY-ma), has been reported to be unknown, though it may mean, “newness”, under the language of the Chehalis people.
“You shall not make for yourself an image in the form of anything in heaven above or on the earth beneath or in the waters below. Exodus 20:4 NIV