Notes:
Cecelia was an illigetimate daughter of Ida Mumma Walls. She was adopted by Samuel and Ida Cecelia (Holtry) Millhouse and raised by them as their daughter. (data from Melissa Swanger)
This appears to have been a "friendly" child placement and adoption. Ida's sister, Laura Mumma, married Charles Holtry. Charles sister, was Ida Holtry who married Samuel Millhouse. It appears that Samuel and Ida Millhouse were unable to have children and they were probably very happy to adopt Ida's illegitimate child. My guess is they even named her, hence she was given Ida's middle name of "Cecelia". Most of the family was unaware of this adoption and Cecelia's biological father's name is unknown. Melissa Swanger stated that Cecelia was identified in a Mumma Family bible.
1920: Shippensburg, Cumberland, Pennsylvania
Street: Walnut Bottom State Road
Samuel Millhouse, head, 44
Ida Millhouse, wife, 43
Cecelia Millhouse, dau, 7