Ahjumawi is a place of exceptional, even primeval, beauty. Brilliant aqua bays and tree studded islets only a few yards long dot the shoreline of Ja-She Creek, Crystal Springs, and Horr Pond. Of the park's 6000 acres, over two thirds of the area is covered by recent (three to five thousand years) lava flows including vast areas of jagged black basalt.

The park is a wilderness area and most of the it is extremely rugged lava rock. Be sure someone knows where you are going and when you expect to return. Visitors should prepare adequately for their visit. Travel off the trails requires proper preparation and equipment.

"Where the waters come together...." is a translation of the word Ahjumawi, which is also the self describing word used by the band of Pit River Native Americans who inhabit the area. The waters which come together are Big Lake, Tule River, Ja-She Creek, Lava Creek, and Fall River. Together they form one of the largest systems of fresh water springs in the country.

Preserved within the Park are lava flows broken by great faults and deep cracks, lava tubes and craters. Freshwater spring flowing from the lava are prominent along the shoreline.

Oak, pine, and juniper forests and slopes of rabbit brush and sagebrush are part of the great variety of vegetation in the area. Abundant wildlife populations are evident all seasons. A great variety of birds including, bald eagles, ospreys, and great blue herons nest or travel through the park. Herds of mule deer forage through much of the park.

Visitors may be inspired by magnificent vistas of Mt. Shasta, Mt. Lassen, and other nearby peaks.

The Ajumawi Ah-joo-MAH-wee people, for whom this park is named, are one of 11 autonomous bands of the federally recognized Pit River Tribe. The Ajumawi have remained in this area, calling this land home for thousands of years.

Ajumawi and its spelling variations Achomawi, Achumawi and Ahjumawi refer to the people who have occupied this area from pre-history to the present. English translations of Ajumawi vary from river people to where the waters come together.

The Ajumawi people built rock fish traps near the shoreline that channeled fresh spring water needed to attract Sacramento suckers and trout. The traps held the fish in a shallow place that allowed them to be caught while spawning in winter. Once the native people caught their self-imposed limit of fish, the traps functioned as protected spawning grounds, ensuring the successful reproduction of the next generation of fish.

Today, descendants of the 11 bands making up the Pit River Tribe still live in an area known as the hundred-mile square in parts of Shasta, Siskiyou, Modoc and Lassen counties. They are keeping their cultural traditions alive for future generations.

By the 20th century, much of the former Ajumawi homeland in the Fall River Valley had been acquired by Pacific Gas and Electric Company PGE to further electrical power development. In 1944, rancher and former lumberman Harry Horr and his wife Ivy purchased 6,000 acres from PGE. The Horrs used the land for cattle grazing and leased it to hunting and fishing clubs.

After Harrys death in the 1960s, Ivy Horr wished to see the land and its resources preserved. In 1975, California State Parks acquired the acreage that is now the park, helped by a generous gift from Mrs. Horr.