Aileen was born to Keaster and Vivian Barns and was raised in the Custer area. She attended Evergreen School from 1st through 8th grade, usually walking the 3 miles to and from school. She graduated from Custer High School in 1949. She then went on to business school in Denver until May 1950. She returned to Custer and worked for the Geological Survey.

In 1951, she married Hank Pepin, they spent their life together ranching and raising a family.

She is survived by her children, Lela (Larry) Larson, MariLynn (Les) Reindl, Wendell (Gerri) Pepin, Jim Pepin, Maxine (Stan) Crandell, Sue (Joe) Sawyer, Tom Pepin, Ray (Anita) Pepin, and Barb (Ken) Irwin; 12 grandchildren; and 19 great grandchildren.

She was preceded in death by her husband, Hank, infant daughter, Roxanne, and her parents.

Per her request there will be no services.

Memorials will go to the Sundance Hospital Comfort Care in Sundance, Wyoming.