1.  Marion County, Ohio, Probate Court Marriage Records, Vols. I-XII, 1824-1902, extracted by Allen L. Potts:

Dunklebarger, Peter

Cupp, Julia Ann

12/05/1832

JP Alonzo Monroe

2.  Census Index:  U.S. Selected Counties, 1810 (Broderbund CD-313):  Can't find Peter, but the 1810 Ohio census was lost.  However, neither can I find Peter's father, Christopher, who is supposedly still alive and living in PA.  There is a John in Northumberland Co., PA, which makes me wonder if Christopher isn't John Christopher (i.e., Johann Kristoph).

3.  1820 Census Index and Digital Images (online at Ancestry.com; Image #1 of 2; extracted by Diana Gale Matthiesen):

1820

OH

Delaware [now Marion] Co.

Marlborough [now Waldo or Prospect] Twp.

p. 108

Ln. 2

Peter Dunkenberger

210010-10010-0-100

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	9 or under	1810-1820	= Son B = Son A
1 male	10-15	1804-1810	= John (b. 1808)
1 male	26-44	1775-1794	= Peter (b. 1787)
1 female	9 or under	1810-1820	= Hannah (b. 1810-15)
1 female	26-44	1775-1794	= Eva
1	persons engaged in agriculture

4.  1830 Census Index and Digital Images (online at Ancestry.com; Image #3 of 7; extracted by Diana Gale Matthiesen):

1830

OH

Marion Co.

Richland Twp.

p. 164

Peter Dunklebarger

020 000 100 - 000 100

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	5-9	1820-1825	= George (b. 1828/9) = William (b. 1826/7)
1 male	40-49	1780-1790	= Peter (b. 1787)
1 female	15-19	1810-1815	= Hannah (b. 1810-15)

Our subject is a widower.  The two boys were tabulated in the wrong age class.

5.  1840 Census Index and Digital Images (online at Ancestry.com; Image #13-14 of 14; extracted by Diana Gale Matthiesen):¤

1840

OH

Marion Co.

Richland Twp.

pp. 73B-74A

Peter Dunkleberger

100 110 010 - 110 021

0100000

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	4 or under	1835-1840	=
1 male	15-19	1820-1825	=
1 male	20-29	1810-1820	=
1 male	50-59	1780-1790	= Peter (b. 1787)
1 female	4 or under	1835-1840	= Nancy (b. 1837)
1 female	5-9	1830-1835	= Sarah (b. 1834/5)
2 females	20-29	1810-1820	= Hannah (b. 1810-15) = ?
1 female	30-39	1800-1810	= Julia (b. ca. 1808)
1	persons engaged in agriculture

There was only one female in the 1810-20 age class in 1830, so the second female cannot be Peter's daughter.  Living next door to Conrad CUPP, probable brother of Julia. 

6.  1850 Census Index/Images (online at Ancestry.com; Image #12 of 30):  Richland Twp., Marion Co., OH, p. 123A, 783/790, enumerated 4 Sep 1850 (extracted by Diana Gale Matthiesen):

Peter Dunklebarger	64	m	Farmer	1800	Pa
Julia M.   "	42	f			O
William    "	23	m	Farmer		O
George     "	21	m	"		O
Sarah      "	15	f			O
Nancy      "	13	f			O
Soloman    "	9	m			O
Lydia      "	7	f			O
Jacob      "	5	m			O

Living next door to Julia's presumed sister, Hester Ann (CUPP) SHAFER. There are no other Dunklebargers/Dunklebergers/etc. in Marion Co. in 1850. 

7.  1860 Census Images (online at Ancestry.com; Image #79 of 36):  Marion P.O., Richland Twp., Marion Co., OH, p. 386A, PN 47, 330/322, enumerated 20 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):

Julia A Dunklebarger	52	M		Farmer	1500	1000	Ohio
Sally M      "	24	F					Do
Solomon      "	18	M		Farmer			Do
Lydia        "	17	F					Do
Jacob        "	15	M		Do			Do

Listed five households from Julia's brother, Peter CUPP.

8.  1870 Census Index/Images (online at Genealogy.com; Image #4-5 of 16 — indexed "Dunkleton"):  Delphos P.O., Hoglin [Hoaglin] Twp., Van Wert Co., OH, Roll 1275 (Book 1), pp. 270B-271A, PN 4-5, 26/26, enumerated 1 Aug 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):

Dunkle???g?? J	25	M	W	Farmer		200	Ohio
"       Jula A	58	F	W				Ohio
Oliver Sarah	34	F	W				Ohio
[next page]
Oliver Ema J	9	F	W				Ohio
"    Man???y	8	F	W				Ohio
Bucan Lida	27	F	W				Ohio
"   Charley	7	M	W				Ohio
"   Isaac	6	M	W				Ohio
"   ?ace?	1	F	W				Ohio

This record was a misery to read.  J. is Julia's son, Jacob; Sarah OLIVER and Lydia BACON are Julia's daughters.

9.   Jane Peppler.  1999.  Marion County, Ohio, Deed Book, Volume I, 1821-1825 (online at Heritage Pursuit):

Page	Grantor	Grantee	Date Signed	Neighbors/Witnesses
87	Nathaniel Wyatt and Anna Wyatt	Peter Dunckleburger	12/20/1823	Samuel Scribner; Israel Jr. Clarke

10.  U.S. Dept. of the Interior, Bureau of Land Management. The Official Land Patent Records Office.

Date	Cert.No.	Land Office	Authority	Patented By	Acres	Aliquot Sec.Twp.Rng	State	County*
8 Oct 1834	7349	Bucyrus	sale-cash	Peter Dankilberger of Marion County Ohio	40	NW¼ NE¼ S14.T6S.R16E	OH	Marion
6 May 1835	9513	Bucyrus	sale-cash	Peter Dunkleberger of Marion County Ohio	40	SW¼ NE¼ S14.T6S.R16E	OH	Marion
*The county is not given on the original certificate, which describes the location of the land solely in terms of Aliquot, Section, Township, and Range.  The county names must have been added to the database at some later time, probably when the certificate data were computerized.

11.  Jacqueline Nein. Dunkelbergers in America, 1728-1997.  Not seen by me.  Said to contain a photograph of Julianna (CUPP) DUNKELBERGER.

12.  LDS.  Family Search: Internet Genealogy Service:  AF - Ancestral File (online at FamilySearch.org).

13.  WorldConnect / Ancestry World Trees (online at RootsWeb.com/Ancestry.com).

14.  Broderbund.  World Family Trees.  Vol. 36, Pedigree No. 1666.  Takes ancestry of Peter well back into Germany.