Data researcher is Douglas Mumma.
Her marriage to Henry Hershey is as follows:
1) The first Reformed Church Records of Lancaster County list the following marriage:
Esther Mumma married Henry Hershey on 7 Feb 1814.
2) The 1850 census of Rapho twp. lists Henry Hershey, age 65 (b: ~ 1785) and his wife, Esther, age 64 (b: ~1786).
3) Esther Mumma, daughter of Christian Mumma, was born 28 Sept 1785 in Rapho Twp. She is identified in her brother's bible.
http://www.mumma.org/cgi-bin/igmget.cgi/n=mumma?I09891
4) Esther's mother, Catherine Mummma, a widow, writes her Will in 1813 in Rapho Twp. and identifies one of her children as Esther Mumma. Therefore Esther Mumma is unmarried in 1813 and living in Rapho twp.
http://www.mumma.org/cgi-bin/igmget.cgi/n=mumma?I08780
Therefore, I suggest that Esther Mumma married Henry Hershey in 1814, not long after her mother's death in 1813.
There are census records of a Henry Hershey living in Rapho Township in the 1890 and 1900 census. It is unclear whether this is the father of Henry Hershey, b. 1784 or someone else. There are a large number of Hershey families living in Rapho twp in the early 1800s
The following census records exist for 1830-1850 which probably relate to this Henry Hershey. The children listed are based on these census records.
1830 PA, Lancaster co., Rapho twp. - Henry Hershey
MALES
10-15 = 2
40-50 = 2 Henry age 46 (the extra male may be a relative)
FEMALES
15-20 = 1
20-30 = 1 (unknown)
40-50 = 1 Esther age 45
1840 census PA, Lancaster County, Rapho twp. - Henry Hershey
MALES
under 5 = 1
20-30 = 1
50-60 = 2 Henry age 56
FEMALES
30-40 = 1 (same unkown as above)
50-60 = 1 Esther age 55
1850 Census, PA, Lancaster Co., Rapho twp., p. 355, dwelling 74
Henry Hershey, 65, farmer, $10,000 real estate, b: PA
Esther " , 64, b: PA
Henry H. " , 4, b: PA
Ann Hershey, 27, widow, b: PA
Fanny Berkheiser, 21, b: PA
Henry nor Esther appear in the 1860 census and it is likely they died before then. It would be interesting to search for a Will for them or a deed for the property.