*Everyone in Robert's family was given birthplace "VA" in the 1850 census, but birthplace "PA" in 1860, so obviously, for that and other reasons, "VA" was a mistake.

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 in Huntingdon Co., PA.

2.  Census Index:  U.S. Selected Counties, 1790 (Broderbund CD-311):  not found.

3.  Census Index:  U.S. Selected Counties, 1800 (Broderbund CD-312):  not found, but there was no 1800 census in Baltimore Co., MD.

4.  1810 Census Index/Images (online at Ancestry.com; Image #1 of 1; extracted by Diana Gale Matthiesen):

1810

PA

Huntingdon Co.

West Twp.

Roll -

p. 24

Line -

E Corban

43010-10100-00

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
4 males	9 or under	1800-1810	= Son F = Son E = Robert (b. 1802/3) = Son D (b. 1800/1)
3 males	10-15	1794-1800	= Son C = Son B = Son A
1 male	26-44	1765-1784	= Ezekiel (b. 1768)
1 female	9 or under	1800-1810	= Daughter A (b. 1810)
1 female	16-25	1784-1794	= Lydia (b. 1786)

5.  1820 Census Index/Images (online at Ancestry.com; Image #3 of 7; extracted by Diana Gale Matthiesen):

1820

PA

Huntingdon Co.

West Twp.

Roll -

p. 97B(98)

Line -

Ezekiel Corbin

230101-30010-0-100

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	9 or under	1810-1820	= Son H = Son G
3 males	10-15	1804-1810	= Son F = Son E = Robert (b. 1802/3)
1 male	19-25*	1794-1801	= Son D (b. 1800/1)
1 male	45 or over	in or bef. 1775	= Ezekiel (b. 1768)
3 females	9 or under	1810-1820	= Sarah (b. 1815-20) = Daughter B = Daughter A (b. 1810)
1 female	26-44	1775-1794	= Lydia (b. 1786)
1	person 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.  By subtracting the number in column three from the number in column four, you can create an age class "19-25."

Listed next to Abraham, Nicodemus, and Caleb CORBIN (list was not alphabetical).

6.  Census Index:  U.S. Selected Counties, 1830 (Broderbund CD-315):  not found.

7.  1840

8.  1850

9.  1860 Census Every-Name Index/Images (online at Ancestry.com; Image #4 of 16):  Henderson Twp., Huntingdon Co., p. 256, PN 4, 25/25, enumerated 6 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):

Henry Steel	40	M		Farmer	175	200	Penna
Sarah     "	40	F					"
[Henry & Sarah's children]
Lydia Corbin	84	F					"

10.  1870 Census Every-Name Index/Images (online at Ancestry.com; Image #10 of 18):  Huntingdon P.O., Henderson Twp., Huntingdon Co., PA, p. 612B, PN 10, 65/70, enumerated 18 Aug 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):

Steel Henry	47	M	W	Farmer	1000	1000	Penna
_____ Sarah	54	F	W	Keeping house			Do
[Henry & Sarah's children]
Corbin Lydia	98	F	W	Living w family			Do

.  Orphans Court Docket, Book E, Page 10, File X, #15 (scan courtesy of Paul CORBIN): 

.  LDS.  Family Search: Internet Genealogy Service: Ancestral File.  Says Ezekiel was born 1757, but the 1810 census shows him born 1765-84.

.  Broderbund.  World Family Trees.  Vol. 1, #2346; Vol. 40, #356.  Says Ezekiel was born 1768, which is consistent with the censuses.

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