The eldest daughter may be Teresa's child or Margaret's.

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

ELI SEEHORN Husband Age at Marriage: 23 Death: 28 Jun 1876 Marriage: 06 May 1831, Adams, Illinois Spouse: TERESA FLINT Source: patron submission

ELI SEEHORN Husband Age at Marriage: 25 Death: 28 Jun 1876 Marriage: 06 Jul 1833, Adams, Illinois Spouse: MARGRET HOGGINS Wife Age at Marriage: 21 Source: patron submission

1b.  Illinois Statewide Marriage Index, 1763–1900:

SEEHORN, John G	BEAN, Almira	12/16/1852	Adams
BEAN, Charles	SEAHORN, Josephine	01/31/1858	Adams

Almira BEAN and Charles BEAN are siblings.  Can't find Eli's marriages, and Adams County (1825-1900) is in the database.  Are the patron submissions to the IGI wrong as to location?

2.  1840 Census Index/Images (online at Ancestry.com, Image #7-8 of 108 — not indexed; extracted by Diana Gale Matthiesen):

1840

OH

Adams Co.

outside the City of Quincy.

Roll M704_54

pp. 19B-20A

Ln. 27

Eli Seehorn

200 011 - 310 010

_______

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	4 or under	1835-1840	= Rufus (b. 1837/8) = John (b. 1833-35)
1 male	20-29	1810-1820	= ?
1 male	30-39	1800-1810	= Eli (b. 1808)
3 females	4 or under	1835-1840	= Josephine (b. 1839/40) = Ellen (b. 1835/6) = Mary (b. 1835/6)
1 female	5-9	1830-1835	= Daughter A
1 female	20-29	1810-1820	= Margaret (b. 1811/2)

Listed four lines below Elihu R. SEEHORN, who is two lines below James M. SEEHORN.  Of the three, only James is indexed.

3.  1850 Census Index/Images (online at Ancestry.com; Image #7-8 of 23 — mis-linked to Image #9, p. 87A):  Town of Fall Creek, Adams Co., IL, Roll M432_97, pp. 86A-86B, 55/57, enumerated 26 Nov 1850, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):

Eli Seehorn	42	M		Farmer	4000	Tenn
Margaret "	38	F				Va
John     "	16	M		Farmer		Ill
Mary     "	14	F				"
Ellen    "	14	F				"
[next page]
Rufus Seehorn	12	M				Ill
Josephine "	10	F				"
Martin A  "	8	M				"
Jefferson "	7	M				"
Sarah M   "	5	F				"
William   "	2	M				"
William Higins	59	M		Farmer	600	Md

A bracket connects Mary and Ellen with the word, "twins."  William HIGGINS is probably Margaret's father.  Listed next to widow Mary SEEHORN (æ 65, b. TN), who is probably Eli's mother.

4a.  1860 Census Every-Name Index and Images (online at Ancestry.com, Image #1-2 of 24):  Payson P.O., Fall Creek, Adam Co., IL, Roll -, pp. 621-622, PN 621-622, 683/689, enumerated 17 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):

Eli Sehorn	51	M		Farmer	24,000	10,000	Tenn
Margarett	47	F					"
John	25	M					Ills
Mary	24	F					"
Rufus	21	M					"
Josephine	20	F					"
Martha	18	F					"
Jefferson	16	M					"
Sarah	14	F					"
[next page]
William Seehorn	12	M					Ills
Elizebeth	8	F					"
Jessee	7	M					"
Isebella	5	F					"
Sarah Hare	16	F					"
Hiram Seehorn	14	M					"

4b.  1860 Census Every-Name Index and Images (online at Ancestry.com, Image #60 of 64):  Quincy P.O., Quincy City (Ward 2), Adams Co., IL, Roll M653_154, p. 108, PN 108, 712/748, enumerated 22 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):

John P Cadogan	35	M		Printer & Publisher	3000	6000	Penn
Fannie    "	30	F					Do
Harry     "	6	M					Ill
Fannie    "	3	F					Do
Ida       "	1	F					Do
Nora Harley	15	F		Domestic			Do
Matilda Cadogan	19	F					Penn
Alexander Johnson	35	M		County Clerk			Ohio
Eli Seehorn	51	M		County Treasurer			Tenn

Eli appears to have been enumerated twice, apparently because he had a second abode in town — which he could well afford!  (See next Source.)

5.  1870 Census Index/Images (online at Genealogy.com; Image #25-26 of 26):  Payson P.O., Fall Creek Twp., Adams Co., IL, Roll 186 (Book 1), pp. 155A-155B, PNs 25-26, 182/173, enumerated 11 Aug 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):

Seehorn Eli	63	M	W	Farmer	95000	45000	Tenn
_______ Margaret	58	F	W	Keepg House			Maryland
Brown Mary	34	F	W	At Home			Ill
_____ Herbert	8	M	W				Ill
_____ Margaret	6	F	W				Ill
Bean Moses M	8	M	W				Ill
____ Margaret J	5	F	W				Ill
Seehorn Jesse	16	M	W	Farm Laborer			Ill
_______ Isabella	14	F	W				Ill
_______ William	22	M	W	Farm Laborer			Ill
[next page]
Cup Theodore	24	M	W	Farm Laborer			MO

Moses M. BEAN and Margaret Josephine BEAN are our subjects' grandchildren, whose mother, Josephine (SEEHORN) BEAN, has apparenly died.  There doesn't appear to be any family connection to Theodore CUPP.

6.  Illinois Public Domain Land Tract Sales (database online at the Illinois State Archives web site and at Ancestry.com):

Purchaser	Seehorn Eli	Seehorn Eli
Residence of Purchaser	unknown	Adams
Aliquot Parts or Lot	SESW	SESWMA
Sec.Twp.Rng	S25.T3S.R8W	S25.T3S.R8W
Meridian	4	4
County of Purchace	Adams	Adams
Acres	40.00	40.00
Price per Acre	1.25	1.25
Total Price	50.00	50.00
Type of Sale	FD	FD
Date of Purchase	01/18/1834	01/18/1834
Volume, Page	v. 701, p. 101	v. 702, p. 198

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

Date	Cert. No.	Land Office	Patented By	Acres	Aliquot Sec.Twp.Rng	Meridian	State	County*
8/6/1838	525	Quincy	Eli Seehorn of Adams County Illinois	40	SE¼ SW¼ S25.T3S.R8W	4th PM	IL	Adams
*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.

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

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