Most secondary sources have James born ca. 1782 or even as early as 1777, but through no less than four censuses (1810-40), his age is 1784-90.  If the 1800 census is correct, then he was born in 1784 (the 1850 census is clearly in error).  Some secondary sources have James dying 10 Jan 1850, but obviously, James was alive to be enumerated in the 1850 census.  Some secondary sources have James dying 1 Oct 1860, but if he were still alive in October, he would have been enumerated in the 1860 census.  Other secondary sources have James dying 1 Jan 1860, and that is the only date that is logically consistent with the facts. 

1.  Marriage Record:

2.  1800 Census Index and Digital Images (online at Ancestry.com; Image #3 of 3 — she is indexed as "Marg Wilkins"; extracted by Diana Gale Matthiesen).  James is not found as head-of-household, which means he is not yet married, but neither do we find his father, Peter.  There is, however, a Margaret WILKINS in Addison Twp., Somerset Co., PA, who is presumably James's widowed mother and with whom James is presumably living.

1800

PA

Somerset Co.

Addison Twp.

p. 147/549

Wilkins Margaret

00200-10010-00

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	16-25	1774-1784	= James = William
1 female	9 or under	1790-1800	= ?
1 female	26-44	1755-1774	= Margaret

If James is in the household, as we would expect, and if this census-taker was accurate, then we have pinned James's birthyear down to 1784.

3.  1810 Census Index and Digital Images (online at Ancestry.com; Image X of X — misindexed as being in Stoney Creek Twp.; extracted by Diana Gale Matthiesen):

1810

PA

Somerset Co.

Addison Twp.

p. 442/461

Wilkins James

10100-30200-00

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	9 or under	1800-1810	= William (b. 1810)
1 male	16-25	1784-1794	= James
3 females	9 or under	1800-1810	= Margaret = Elizabeth = ?
2 females	16-25	1784-1794	= Abigail = ?

It's hard to say who the other females are.  The list was alphabetized, so no neighborhood reconstruction is possible.

There was a problem with this record, which is why I haven't given the usual image number above.  Here is the message I sent to Feedback at Ancestry.com:

There is a problem with the indexing and images of the 1810 census of Somerset Co., PA.  If you look at the first image of Southampton Twp. (image 1 of 2), you'll note that at the top of the page are four names and a tally from the previous township.  That is, Southampton Twp. does not start at the top of the page.  Note the page numbers of this page are 442 (upper left) and 461 (center right).  The four names at the top are:  Wilkins James; Wilson William; Wass George; and Wersing John.  You have these names indexed as being in Stoney Creek Twp. and you have them linked to this page in Southampton Twp.  This is a double error because if you'll check the last page of Addison Twp., you'll see it is page number 441/461.  That is, the four names should be indexed as being in Addison Twp., not Stoney Creek.  And you need to duplicate image 1 of Southampton and add it to the end of Addison.

If the image is still out of place when you give it a try, perhaps you might message them, too.

4.  1820 Census Index and Digital Images (online at Ancestry.com; Image #6 of 7; extracted by Diana Gale Matthiesen):

1820

PA

Somerset Co.

Addison Twp.

p. ?

Wilkins James

210010-22010-0-100

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	9 or under	1810-1820	= John (b. 1820) = Andrew (b. 1814)
1 male	10-15	1804-1810	= William (b. 1810)
1 male	26-44	1775-1794	= James (b. 1784-90)
2 females	9 or under	1810-1820	= Hilah (b. 1818) = Sarah (b. 1811)
2 females	10-15	1804-1810	= Margaret = Elizabeth
1 female	26-44	1775-1794	= Abigail (b. 1784-90)
1	person engaged in agriculture

List is alphabetized, so no neighborhood reconstruction is possible.

5.  1830 Census Index and Digital Images (online at Ancestry.com; Image #11 of 15; extracted by Diana Gale Matthiesen):

1830

PA

Somerset Co.

Addison Twp.

p. 28

Wilkins James

110 200 100 - 011 010 100

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	4 or under	1825-1830	= Ami (b. 1826/7)
1 male	5-9	1820-1825	= John (b. 1820)
2 males	15-19	1810-1815	= Andrew (b. 1814) = William (b. 1810)
1 male	40-49	1780-1790	= James (b. 1784-90)
1 female	5-9	1820-1825	= Mary Ann (b. 1824)
1 female	10-14	1815-1820	= Hilah (b. 1818)
1 female	20-29	1800-1810	= Margaret or Elizabeth
1 female	40-49	1780-1790	= Abigail (b. 1784-90)

We're short some females.  Still, there can be no doubt this is our family.  List is alphabetical, so no neighborhood reconstruction is possible.

6a.  1840 Census Index and Digital Images (online at Ancestry.com; Image #11 of 20; extracted by Diana Gale Matthiesen):

1840

PA

Somerset Co.

Addison Twp.

p. 7

James Wilkins

001 010 010 - 001 100 010

0100000

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	10-14	1825-1830	= Ami (b. 1826/7)
1 male	20-29	1810-1820	= John (b. 1820)
1 male	50-59	1780-1790	= James (b. 1784-90)
1 female	10-14	1825-1830	= Mary WEIMER (b. 1827/8)
1 female	15-19	1820-1825	= Mary Ann (b. 1824)
1 female	50-59	1780-1790	= Abigail (b. 1784-90)
1	person engaged in agriculture

Listed two lines below Abigail's father, Alexander McCLINTOCK, and two lines above our subjects' son, Andrew WILKINS (200 010 - 120 010 — making him born 1810-20).

6b.  1840 Census Index and Digital Images (online at Ancestry.com; Image #9 of 20; extracted by Diana Gale Matthiesen):

1840

PA

Somerset Co.

Addison Twp.

p. 5B

Thomas Bird

000 010 - 000 000

Is this Thomas BIRD the widowed husband of Mary Ann WILKINS?  Did she die without issue?  (Not found in the 1850 census.)

7a.  1850 Census Index/Images (online at Ancestry.com; Image #37 of 40):  Addison Township, Somerset Co., PA, p. 202A, 221/243, enumerated 5 Aug 1850 (extracted by Diana Gale Matthiesen):

James Wilkins	51	M	Farmer	1500	Pa
Abigail Wilkins	54	F			"
John Wilkins	28	M	Labourer	800	"
Ann?/Ami? Wilkins	23	F			"
Mary A Weimer	22	F			"
Mary A Cupp	10	F			"

James and Abigail are both in their 60's, not 50's.  It looks like the enumerator may have gotten John's age wrong, too, as well as getting Ami's gender wrong.   I don't know who Mary WEIMER is, but her tie to the family seems strong as she was either living with or next door to the WILKINS in 1840, 1850, and 1860.  [Hila (WILKINS) CUPP's brother-in-law, Aaron CUPP, married a WEIMER.]  Mary CUPP would appear to be their granddaughter (d/o Frederick CUPP & Hila WILKINS), though her middle initial should be "J," for Jane, but in which case she was enumerated twice, once with her parents and once with her grandparents.  Living two doors down from son, Andrew. 

7b.  1850 Census Index/Images (online at Ancestry.com; Image #37 of 40):  Addison Township, Somerset Co., PA, p. 202A, 223/245, enumerated 5 Aug 1850 (extracted by Diana Gale Matthiesen):

Andrew Wilkins	36	M	Farmer	800	Pa
Caroline Wilkins	36	F			"
Sarah J Wilkins	17	F			"
Annia? Wilkins	9	M			"
Mary E Wilkins	7	F			"
Simantha E Wilkins	5	F			"
Eliza Wilkins	3	F			"

Living two doors down from Andrew's parents.

7c.  1850 Census Index/Images (online at Ancestry.com; Image #35-36 of 40):  Addison Twp., Somerset Co., PA, pp. 201A-201B, 212/234, enumerated 5 Aug 1850 (extracted by Diana Gale Matthiesen):

Wm Wilkins	39	M	Farmer	2150	Pa
[next page]
Louisa Wilkins	35	F			Pa
Levi Wilkins	15	M			"
Margaret Wilkins	14	F			"
James Wilkins	12	M			"
John Wilkins	10	M			"
Louisa Wilkins	8	F			"
Wm W Wilkins	6	M			"
Rosanna Wilkins	4	F			"
Alfred Wilkins	2	M			"
Levida Wilkins	1	F			"

8a.  AIS (Accelerated Index System) 1860 Census Index (online at Ancestry.com):  James not found, as expected.

8b.  1860 Census Images (online at Ancestry.com; Image #19 of 684):  Addison P.O., Addison Twp., Somerset Co., PA, p. 19, PN 63, 415/415, enumerated 2 Jul 1860 (extracted by Diana Gale Matthiesen):

Ami Wilkins	33	m		Farmer		75	Pa
Mary A	31	f		Spinster			"
Margaret A	5	f					"
Laura J	5	f					"
Mary A	3	f					"
Emma E	5/12	f					"

Living next door to Mary WIEMER (æ 21, b. PA).  This enumerator called all the wives and other adult women "spinsters," unless they had some other occupation (e.g., seamstress, weaver).

8c.  1860 Census Images (online at Ancestry.com; Image #18 of 684):  Addison P.O., Addison Twp., Somerset Co., PA, p. 18, PN 62, 412/412, enumerated 30 Jun 1860 (extracted by Diana Gale Matthiesen):

Jno Wilkins	41	m		Farmer		300	Pa
Cyntha	28	F		Spinster			"
James M	9	m					"
Ann S	7	f					"
John F	6	m					"
Catharine	4	f					"
Elisabeth	2	f					"

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

10.  Messages in the Wilkins Family Genealogy Forum (online at GenForum.com).