.  Asahel "Asa" CORBIN, Jr., b. 1805-14
.  Ezekiel CORBIN, b. 1802/3 
.  Benjamin CORBIN, b. 1805-10 
.  Elijah CORBIN [twin], b. 1807-15
.  Elisha CORBIN [twin], b. 1807-15 
.  Actoris / Actious / Achias / Axius / Achiah CORBIN, b. 1810-20

Said to have had these children
.  Nicodemus CORBIN
.  William CORBIN
.  Abram CORBIN
.  Eleanor "Ellen" CORBIN, b. 1819

Some sources say Achiah was born ca. 1802 and died 16 Nov 1881 in Miller Twp., Huntingdon Co., PA.  The death date is reasonable, though she was living in Barree Twp. in the 1880 census.  There is no scriptural name, "Achiah," though there is an Achaia (which is Greek). 

1.  Letter, dated 19 Jun 1858, from Keziah (GREENLAND) SHANAFELT (click her link for a full transcription) of Clarion Co., PA, to her son, Thomas.  Keziah is a granddaughter of Benjamin & Sarah (SIAS) CORBIN.  The letter is in the possession of  Laurel Shanafelt Powell of Colorado, and Lorinda Clendenon Greenland generously posted a transcription at her web site. 

... Uncle Ezekial and Asahal married sisters, Nelly and Lidaiu Corbin, Uncle William Corbin's daughters.  They both died at the ridges near Millcreek.  Their widows are living yet as far as I know...

The Mill Creek to which Keziah refers is about 10 mi SE of Huntingdon, Huntingdon Co., PA. 

2.  1800 Census Index and Digital Images (online at Ancestry.com; Image #2 of 3; extracted by Diana Gale Matthiesen):¤•

1800

PA

Huntingdon Co.

Barree Twp.

Roll 40

p. 158

Ln 23

Asahel Corbin

30100-00100-00

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
3 males	9 or under	1790-1800	= ? = ? = ?
1 male	16-25	1774-1784	= Asahel (b. 1774)
1 female	16-25	1774-1784	= Eleanor (b. 1779)

Listed between Isaac GREEN and John GREEN.

3.  1810 Census Index and Digital Images (online at Ancestry.com):  not found, and I checked every page of Huntingdon Co., PA, line-by-line.

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

1820

PA

Huntingdon Co.

West Twp.

p. 99

Eleanor Corbin

223300-10110-0-300

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	9 or under	1810-1820	= Elisha  = Elijah
2 males	10-15	1804-1810	= Benjamin = Ezekiel
3 males	16-18	1801-1804	= ? = ? = ?
1 female	9 or under	1810-1820	= Achiah
1 female	16-25	1794-1804	= ?
1 female	26-44	1775-1794	= Eleanor (b. 1779)
3	persons engaged in agriculture
*In the 1820 Census, the third column is age class 16-18 and the fourth column is age class 16-25; therefore, any individual in column three is duplicated in column four.

5.  1830 Census Index and Digital Images (online at Ancestry.com; Image #7 of 20; extracted by Diana Gale Matthiesen):

1830

PA

Huntingdon Co.

West Twp.

p. 141A

Elen Corban

000 151 000 - 001 010 010

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	15-19	1810-1815	= ?
5 males	20-29	1800-1810	= Elijah = Elisha = Benjamin = ? = ?
1 male	30-39	1790-1800	= ?
1 female	10-14	1815-1820	= ?
1 female	20-29	1800-1810	= Achiah
1 female	50-59	1770-1780	= Eleanor (b. 1779)

Listed next to John KEMP, who is next to Henry HIGHT, who is two lines from George HIGHT. 

6.  1840 Census Index and Digital Images (online at Ancestry.com; Image #1 of 22; extracted by Diana Gale Matthiesen):

1840

PA

Huntingdon Co.

West Twp.

pp. 190B-191A

Benjamin Corbin

000 002 100 - 110 020 001

0300000

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	30-39	1800-1810	= Elisha = Elijah
1 male	40-49	1790-1800	= Benjamin
1 female	4 or under	1835-1840	= Emily (b. 1837/8)
1 female	5-9	1830-1835	= ?
2 females	20-29	1810-1820	= Achiah = ?
1 female	60-69	1770-1780	= Eleanor (b. 1779)
3	persons engaged in agriculture

Listed next to George HIGHT.

7.  Census Microfilm Records:  Pennsylvania, 1850 (Broderbund CD-305, Disk 5):  West Twp., Huntingdon Co., PA, Roll 784, p. 93, 253/256, enumerated 10 Sep 1850 (extracted by Diana Gale Matthiesen):

Benj Corban	40	M	farmer	1300	Penna
Ellen   "	70	F			Md
Actoris "	30	F			Penna
Emily   "	12	F			"
Elijah  "	35	M	Laborer		"
Elisha  "	35	M	"		"

Elijah and Elisha are tied with wiggly lines, presumably indicating they are twins, which they are.  Who is Emily?

8.  1860 Census Images (online at Ancestry.com; Image #4 of 10):  Huntingdon P.O., Oneida Twp., Huntingdon Co., PA, p. 426, PN 4/25, 24/24, enumerated 12 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):

Ellen Corbin	80	F					Maryland
Benjamin	55	M		Farmer	1000	300	Penn
Elijah	50	M		Farm Laborer			"
Elisha	50	M		Day [Laborer]			"
Achias	48	F					"

Elijah and Elisha are marked "Twins."  Listed next to John HALL, who is next to Asa & Mary CORBIN.  Several GREENs nearby. 

9.  1870 Census Images (online at Ancestry.com; Image #3 of 10):  Huntingdon P.O., Oneida Twp., Huntingdon Co., PA, p. 669A, PN 3, 27/27, enumerated 26 Aug 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):

Corbin Benjamin	65	M	W	Farmer	1500	1500	Pennsylvania
______ Elisha	57	M	W	Farm Laborer			Do
______ Elijah	57	M	W	Do			Do
______ Achiah	55	F	W	At Home			Do

Listed next to Micajah CORBIN, Jr.

10a.  1880 United States Census and National Index (LDS Family History Resource File: CD-ROM Library):

Census Place: Barree, Huntingdon, Pennsylvania
Source: FHL Film 1255134; NARA Film T9-1134; Pg 72C
	Relation	Sex	Marr	Race	Age	Birthplace	Occupation	Fa	Mo
Elizah CORBIN	Self	M	S	W	72	PA	Retired	VA	PA
Actious CORBIN	Sister	F	S	W	70	PA	Keeping House	VA	PA

See next record.

10b.  1880 Census Images (online at Ancestry.com; Image #3 of 23):  Barree Twp., Huntingdon Co., PA, p. 72C, PN 3, SD 7, ED 184, enumerated 2/3 Jun 1880, official enumeration date 1 Jun 1880 (extracted by Diana Gale Matthiesen):

1880:  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	8	9	13	17	20	22	23	24	25	26
11	11	Corbin Elijah	W	72	M		/	Retired	/		/	/	Penna	Virginia	Penna
		"   Actious	W	70	F	Sister	/	Keeping house		/		/	Penna	Virginia	Penna

And now we know at least partly why these children went unmarried:  a tick in column 17 means deaf and dumb, while 20 means disabled (23 means cannot read; 24 means cannot write).  Both of their parents were born in Maryland.

11.  Broderbund.  World Family Trees.  Vol. 40, Pedigree No. 356.

12.  LDS.  Family Search: Internet Genealogy Service: Ancestral File.  Has Elijah and Elisha b. 1800 and Asahel b. 1813.