It is possible that prehistoric people, from whom the Chumash descended, inhabited the local area and used Poly Canyon as long as 9,000 years ago. The Chumash subsisted primarily on marine organisms, but made annual migrations inland to forage on seasonal foods, primarily seeds. The seeds, such as acorns, chia, and islay, were collected and ground, using bedrock mortars and pestles, or stored whole. As mentioned, the Chumash may have used fire for hunting and agricultural development, but none has been documented in the Canyon. Chumash probably did not have any large living site in the Canyon as they would have needed more flat areas. There are very few large, flat rock outcrops in the vicinity of water to be used for bedrock mortars.

The time of Spanish exploration lasted from the late 1500s until the early 1700s, and Mission San Luis Obispo de Tolosa was founded in 1772. With local settling of the Spanish, the first crops were planted, and herds of cattle, sheep, and horses were brought. When California became a Mexican territory in 1822, mission lands were divided into cattle ranches using natural features for boundaries. Rancho Potrero de San Luis Obispo (Figure 12) bordered on the west with Rancho el Chorro and, on the southeast, it roughly followed the Arroyo del Potrero. It was given to Juan Alvarado and María Concepción Borondo in 1842. The creek was later named Brizzolara Creek, after Bartolo Brizzolara, a prominent local. The name has been recorded as "Brizziolari" Creek on some government documents such as U.S.G.S. soils maps. The land passed through several ownerships and eventually to Sylvia and Dorothy Peterson. The Petersons grazed cattle on their ranch. Their houses, which stand just northeast of the Botanic Garden, are still used.

California's statehood and the Gold Rush came in 1848 and, with them, a local expansion of cattle and horse ranching. There is an incipient, abandoned mine in Poly Canyon, doubtfully productive (at least for precious metals). San Luis Obispo was organized into a town in 1856. The stagecoach line through San Luis Obispo from Los Angeles to San Francisco was completed in 1861. Cattle ranching declined with the drought of 1862-1864. Many ranchers were forced to sell off portions of their land, often to dairy farmers who were beginning to prosper. In 1876 San Luis Obispo was officially recognized as a city, and the Pacific Railroad line over Cuesta Grade was completed.

Cal Poly was established in 1901. Between 1901 and 1903, Johnson Ranch, a cattle ranch, was purchased by the College. This brought into State ownership the road winding through the Canyon (now "Poly Canyon Road"), land halfway up the Canyon, and the surrounding hills. The area was also called "Curlew" Canyon from about 1930 to 1935 after a caretaker of Johnson ranch. Alfalfa and poultry were raised just below the Canyon. Hogs were penned near the Canyon entrance and were allowed to forage throughout the Canyon. From 1946 to 1950, the University razed all the Johnson Ranch structures.

Along the southeastern border of what was the Peterson Ranch and the northern border of what is now the Botanic Garden, Cuesta Ranch (the "Miossi lease" on agricultural maps) was a Mexican land grant whose original owners were unable to afford its upkeep. In the 1870s it was homesteaded and eventually purchased by the Goldtrees. In 1876 they built a house and established a dairy farm on the west-facing slope where the cypress grove is (east of the Peterson Ranch houses). In 1902 Frank Tate bought the ranch, then in 1917 sold it to Ben Miossi. Mr. Miossi built a new house on the "front" of the property (in Cuesta Canyon) and, around the time of World War II, converted to cattle ranching. The old Cuesta Ranch structures in Poly Canyon were slowly taken apart by vandals and by Mr. Miossi, who used what materials he could for his new ranch. The current owner, Harold Miossi, was born on the property and continues cattle ranching today.

In 1948, Dr. Robert F. Hoover proposed establishing a native botanic garden for use by botany and ornamental horticulture classes. Sixty-five acres south of the fence line with the Peterson Ranch were acquired in 1955 for this purpose. The area includes western and eastern slopes of Poly Canyon extending to the west, and north-northeast-facing slopes (refer back to Figure 1). Numerous non-native specimens were eventually planted in the botanic garden, against Dr. Hoover's wishes.

Today the Canyon is best known as Poly Canyon and it includes lands belonging to both the State of California and the Miossi and Serrano Ranches. (The Serrano Ranch runs along the western fringe of the Canyon.) The Botanic Garden is under the care of the Biology Department, and classes such as Field Botany use it regularly for educational purposes. Other parts of the Canyon are also used frequently by classes in the Biology Department. Plant and animal identification and natural history walks are a regular part of Canyon life, and species inventories have been the subject of many senior projects and special problems. Numerous studies on plant community structure and the relationships among plants and animals are performed, particularly in the "Ecological Study Area" on the southwest-facing slope just west of the Creek above the cattle yard. Every spring, jars and long-handled nets identify entomology students on the hunt for elusive insects for their class collections.

The ten-acre Design Village was purchased by the College in 1950-52 from Sylvia and Dorothy Peterson. It is located just southwest of the Peterson Ranch house. The Architecture Department has used this area, also called "Design Village," for the construction of several experimental student projects. (refer back to Figure 1)

The Animal Science Department uses the Canyon mostly (95%) for grazing beef cattle and occasionally for grazing horses and calving. Grazing lands are seeded with non-native grasses.

Other departments make use of numerous natural features in the Canyon. Classes such as Introduction to Soils, Soil Morphology, Water Quality, Range Management, Geology, and Recreation Administration's Environmental Education use the Canyon regularly. These departments have had numerous students work on senior projects and/or special problems in the Canyon. During the annual open house (Poly Royal), the Recreation Administration Department has hosted environmental education programs for fourth and fifth graders in the Canyon.

The landfill (refer back to Figure 1) has not been used for dumping waste products since the mid-1970s. Redrock, used in surfacing Cal Poly roads and corrals is extracted from the landfill, and fill dirt, such as sediments accumulated after floods, are put into the site. The County of San Luis Obispo, in conjunction with the Environmental Health and Safety Department on campus, checks the landfill for leakage of old waste products and other environmental hazards on an annual basis.

Work aside, the Canyon is used daily. Students, staff, faculty, local residents, and visitors stroll, hike, jog, ride horses, mountain bike, fly kites, picnic, and birdwatch in the Canyon. Figure13 shows the trails in Poly Canyon.