The Keystone Historical Museum (410 Third St., 605/666-4847, www.keystonehistory.com, June–Aug. Mon.–Sat. 10 a.m.–3 p.m., closed Sun., closed in off-season, free) is housed in the old Keystone school, built in 1900. Two of the primary collections of the museum include a gem and mineral collection and memorabilia that once belonged to Carrie Ingalls Swanzey.

Carrie Ingalls was the sister of Laura Ingalls Wilder, who was famous for authoring a series of books about life on the prairie, including Little House on the Prairie, which was turned into a popular television series.

Carrie Ingalls is an interesting example of an independent Western woman. She grew up in DeSmet, South Dakota, earned her teaching certificate, eventually ended up in the newspaper business, and at one time homesteaded on her own land near Philip, South Dakota.

In 1911, Carrie moved to Keystone, where she managed the Keystone Register newspaper until she married at the age of 42. History buffs and those interested in the history of women in the West will especially enjoy visiting the museum.