In 1935, Ruth Teuscher purchased 40 acres of land in the Town of Somers in northern Kenosha County. Inspired by a grove of native hawthorn trees growing along the Pike River, she and her sister, Margaret, both teachers in Racine, named the property Hawthorn Hollow. They soon posted the land as a wildlife refuge, the first step toward developing what is now Hawthorn Hollow Nature Sanctuary and Arboretum.

Reflecting the Teuscher sisters' interests, Hawthorn Hollow today combines nature, history and horticulture. Two miles of nature trails wind through the woods of the Pike River Valley. In spring, the forest floor is covered with native wildflowers. During the spring and fall migrating seasons, many songbirds stop at Hawthorn Hollow. Others remain year 'round, making Hawthorn Hollow one of the finest bird watching spots in the area.

Unique to Hawthorn Hollow is a small but valuable area of original prairie, reflecting the type of vegetation that once covered much of the Midwest. Hawthorn Hollow also boasts a restored prairie, perennial gardens, a butterfly garden and a dwarf conifer collection.

To assure the preservation of Hawthorn Hollow, the Teuscher sisters deeded their property to the Hyslop Foundation in 1967. Since then, its Board of Trustees has made many significant contributions to Hawthorn Hollow.

With the help of outside contributions, three historic buildings were moved to the property in 1967: the original Pike River School (1847), the second Pike River School (1906), and the original Somers Town Hall (1859).

The Hyslop Foundation also established a twelve-acre arboretum which features a variety of trees and shrubs, including Ruth's lilac collection, which runs along the south edge of the arboretum.

The Friends of Hawthorn Hollow was established in 1988 to help preserve, maintain and further improve Hawthorn Hollow. This organization provides financial and maintenance support through memberships, fund-raising events, boutique sales and volunteer work days.