There are Greenville's in three states in PA:  Clearfield, Mercer, and Montgomery.

1.  Marriage Index:  Indiana, 1851-1900 (Broderbund CD-243):

Capp, Valentine

Brown, Eliza Jane

Nov 27, 1864

Huntington Co.

2.  1870 Census Images (online at Ancestry.com; Image #14 of 42):  Huntington P.O., Rockcreek Twp., Huntington Co., IN, p. 177B, PN 14, 104/102, enumerated 7 Jul 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):

Cupp Valentine	32	M	W	Farmer?	1400	500	Ohio
____ Eliza	24	F	W	Keeping house			Pennsylvania
Armstrong Charles	11	M	W	At Home			Indiana
Brown Charles	9	M	W				Indiana

Listed next door to Alexander & Elizabeth BROWN, whom I would have pegged as Eliza's parents, but see next record.

3.  1880 United States Census and National Index (LDS Family History Resource File: CD-ROM Library):

Census Place: Markle, Huntington, Indiana
Source: FHL Film 1254285; NARA Film T9-0285; Pg 588B
	Relation	Sex	Marr	Race	Age	Birthplace	Occupation	Fa	Mo
Valentine CUPP	Self	M	M	W	42	OH	Undertaker	OH	--
Jane CUPP	Wife	F	M	W	39	PA	Keeping House	PA	PA
Catharine BROWN	GMother	F	W	W	69	PA		PA	--

4.  1890 Census:  the 1890 census population schedules were destroyed.

5.  1900 Census Index/Microfilm (online at Genealogy.com):  Markle Town, Rockcreek Twp., Huntington Co., IN, p. 224A, SN 3, SD 11, ED 87, enumerated 4 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):

1900:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).
1	2	3	4	5	6	7	8	9	10	13	14	15	19	20	22	23	24	25	26	27
66	68	Cupp Valentine	Head	W	M	Jun 1836	64	M	36	OH	VA	PA	Carpenter	0	Y	Y	Y	O	F	H
		____ Eliza J	Wife	W	F	Aug 1843	56	M	36	PA	PA	PA			Y	Y	Y

Valentine's and Eliza's birthdates and ages were very hard to read because someone had written over them.

6.  Email from Sarah Nesbeitt, who cites family bible records and Valentine's obituary (in local newspaper).