1.  LDS.  Family Search: Internet Genealogy Service:  IGI - International Genealogical Index (online at FamilySearch.org).

Robert A. STROUP Death: 04 May 1865 Marriage: 13 May 1858, Millcreek Tp, Clarion, Pennsylvania Spouse: Rachel E. DAVID Source: patron submission

Arnold H. Stroup; Birth: 01 Mar 1859, Millcreek Tp, Clarion, Pennsylvania Lincoln S. STROUP; Birth: 06 Aug 1861, Millcreek Tp, Clarion, Pennsylvania Father: Robert A. Stroup; Mother: Rachel E. David Source: patron submission

2.  1850 Census Every-Name-Index/Images (online at Ancestry.com):  Rachael DAVIS (æ 10, b. PA) is living in Limestone Twp., Clarion Co., PA (p. 46A), with her parents, William DAVIS (æ 38, b. PA) & Mary (æ 36, b. PA), plus siblings.

3a.  1860 Census Images (online at Ancestry.com; Image #10 of 10 — indexed "Straupt"):  Clarion P.O., Millcreek Twp., Clarion Co., PA, p. 340, PN 10, 63/67, enumerated 31 Aug 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):¤•

Robert Stroupe	24	M		Lumberman	700	250	Penna
Rachel    "	20	F					"
Arnold H  "	1	M					"

Listed two household from Robert's parents, Philip & Mary Ann (DEAN) STROUP. 

3b.  1860 Census Every-Name-Index/Images (online at Ancestry.com):  Rachel DAVIS (æ 20, b. PA) is enumerated in Mill Creek Twp., Clarion Co., PA (p. 337A), with her parents, William DAVIS (æ 48, b. PA) & Mary (æ 46, b. PA), plus siblings, including Sarah (æ 6, b. PA).  How did Rachel end up enumerated twice?  Was she home on a visit?

4a.  1870 Census Every-Name-Index/Images (online at Ancestry.com, Image #4 of 13):  Fisher P.O., Mill Creek Twp., Clarion Co., PA, Roll M593_1326, p. 528B, PN 4, 23/23, enumerated 29 Jun 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):¤

Stroup Rachel	30	F	W	Keeping house widow		300	Penna
______ Sarah E	16	F	W				"
______ Arnold	11	M	W				"
______ Abraham	9	M	W				"

Sarah was born well before Rachel & Robert married; she appears to be Rachel's younger sister.  Listed next to William DAVIS (æ 58, b. PA) & wife Mary (æ 56, b. PA), and four children, but not Sarah.

4b.  1870 Census Index/Images (online at Genealogy.com; Image #35 of 50):  Titusville P.O., Titusville (Ward 1), Crawford Co., PA, Roll 1331 (Book 1), p. 622A, PN 35, enumerated 6 Jun 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):¤•

Stroup Arnold H

11

M

W

Penna

Did Arnold get enumerated twice?  Or is this a different Arnold?  One of 192 pupils in the "Pennsylvania State Soldiers Orphans School."