Here is the only family I know of in 1880 in Carbon County PA with a daughter named Mary and being 5 years of age, as well as 2 other families in nearby counties:
Franklin Twp., Carbon County, PA 1880 Census E.D. 123, Page 28 ZEIGENFUS family: John ...... 42 PA PA PA Laborer Sarah ..... 36 PA PA PA Harrison .. 10 PA PA PA Clarra ..... 9 PA PA PA John ....... 8 PA PA PA Mary ....... 5 PA PA PA Susanna ... 83 PA PA PA Widow
West Rockhill, Bucks County, PA 1880 Census E.D. 162, Page 11 ZIEGENFUSS family Oliver H. . 41 PA PA PA Cigarmaker Mary ...... 25 PA PA PA John ....... 8 PA PA PA Joseph ..... 7 PA PA PA Elizabeth .. 6 PA PA PA Mary ....... 5 PA PA PA Emma ....... 3 PA PA PA Catherine .. 1 PA PA PA Elizabeth . 67 PA PA PA Widow
Johnsonville, Northampton County, PA 1880 Census E.D. 103, Page 32 ZIEGENFUSS family Andrew .... 25 PA PA PA Farmer Elizabeth . 26 PA PA PA Mary ....... 5 PA PA PA Gilbert .... 4 PA PA PA Frank ...... 3 PA PA PA Daniel ..... 1 PA PA PA Peter P. .. 74 PA PA PA Unkle, retired farmer
Since the last name is the original version of SIGAFOOS, these 3 Marys may not be your Mary.I have a rather thorough listing of 1880 families only in Carbon, Bucks and Northampton counties of PA.These 3 counties were the most populous of the Sigafoos and Ziegenfuss families, but others are also found in Lehigh, Berks, Philadelphia, Monroe, Schuylkill, Westmoreland, Indiana, Jefferson and Lawrence counties which I haven't researched yet.
You may want to try your own search for a 5 year old Mary Sigafoos in the 1880 Pennsylvania Soundexes.
Would her marriage record include her parents' names?