— born in PA:
  2.  Elizabeth CORBIN, b. 1781/2
  3.  William CORBIN, b. 11 March 1784 
  4.  Lydia CORBIN, b. 1786?, more likely bef. 1784 
  5.  Mary CORBIN, b. 1789/90
  6.  Nancy CORBIN, b. 31 Jan 1790
  7.  Abraham CORBIN, b. 1793; d. 1847 
  8.  John CORBIN, b. 1794/5/6/7 
  9.  David G. CORBIN, b. 1796/7/8/9 
10.  Sarah "Sally" CORBIN, b. ca. 22 Mar 1799
11.  Sophia CORBIN, b. 1800-04; d. 1840, IN — to OH immediately after marriage, then to IN 
12? (Son) CORBIN, b. 1804-10

1.  Marriage Record:

2.  Census Index:  Colonial America, 1607-1789 (Broderbund CD-310):  not found.

3a.  Census Index:  U.S. Selected Counties, 1790 (Broderbund CD-311):  not found.

3b.  1790 Census Index and Digital Images (online at Ancestry.com):  not found.  I checked every page of Huntingdon Co. line-by-line and didn't find William; however, the bottom edge of some pages were so underexposed the names cannot be read.

3c.  Family Quest Archives:  Pennsylvania Federal Census 1790:  Berks, Chester, Delaware, Huntingdon, Mifflin (part), Luzerne, Dauphin, Northampton, Cumberland, Fayette, Westmoreland (part), Bucks, and Lancaster Counties.  Heritage Quest CD M637-8:  not found, but these images have the same unreadable sections at the bottom of pages.

4.  1800 Census Index and Digital Images (online at Ancestry.com; Image #2 of 7; extracted by Diana Gale Matthiesen):¤•

1800

PA

Huntingdon Co.

Huntingdon [now Juniata] Twp., South of the Juniata

Roll 40

p. 153

Ln 14

William Corbin

01001-10310-00

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
0 males	9 or under	1790-1800	= David (b. 1796-99) = John (b. 1794-97) = Abraham (b. 1793)
1 male	10-15	1784-1790	= William (b. 1784)
1 male	45 or over	in or bef. 1755	= William (b. 1744)
1 female	9 or under	1790-1800	= Sarah (b. 1799)
3 females	16-25	1774-1784	= Lydia (b. 1786?) = Elizabeth (b. 1781/2) = Eleanor (b. 1779)
1 female	26-44	1755-1774	= Betsy

Where are the boys?!  Surely this is our subject, and surely this is enumerator error.  William is the only CORBIN in the township.

5.  1810 Census Index and Digital Images (online at Ancestry.com; Image #7 of 9; extracted by Diana Gale Matthiesen):¤•

1810

PA

Huntingdon Co.

Huntingdon [now Juniata] Twp.

Roll

p. 25/132

Ln

Wm Corban

02201-11101-00

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	10-15	1794-1800	= David (b. 1798/9) = John (b. 1794/5)
2 males	16-25	1784-1794	= Abraham (b. 1793) = William (b. 1784)
1 male	45 or over	in or bef. 1765	= William (b. 1744)
1 female	9 or under	1800-1810	= Sophia (b. 1800-04)
1 female	10-15	1794-1800	= Sarah (b. 1799)
1 female	16-25	1784-1794	= Nancy (b. 1790)
1 female	45 or over	in or bef. 1765	= Betsy

Listed next to daughter and son-in-law, John & Elizabeth (CORBIN) REIDENOUR. 

6.  1820 Census Index and Digital Images (online at Ancestry.com; Image #3 of 6; extracted by Diana Gale Matthiesen):¤•

1820

PA

Huntingdon Co.

Porter [now Juniata] Twp.

p. 75

William Corbin

010101-00101-0-200

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	10-15	1804-1810	= Son?
1 male	19-25*	1794-1801	= David (b. 1798/9)
1 male	45 or over	in or bef. 1775	= William (b. 1744)
1 female	16-25	1794-1804	= Sophia (b. 1800-04)
1 female	45 or over	in or bef. 1775	= Betsy
2	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.  By subtracting the number in column three from the number in column four, you can create an age class "19-25."

Listed 15 lines from sons-in-law, John REIDENOUR and Reading BYE. 

7.  Letter, dated 19 Jun 1858, from Keziah (GREENLAND) SHANAFELT (click Keziah's 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. 

My mother's father was Benjamin Corbin...  I never saw Grandfather Corbin.  He died when I was young.  I often saw his youngest brother William.  He came to Huntingdon. While young he married Betsy Brown, sister to Mrs. Weaver's father.  He lived near Raystown Branch but died in Huntingdon.  Many of his descendants live there yet.  He had a sister, lived in Ohio.  Her family was said to be very wealthy.  I think her name was Marsh.  He had other brothers, too, but I am unacquainted with their history...

If William did marry Betsy as a young man, then we have a problem with dates and ages.  William's sister, Sophia, married Thomas MARSH. 

8.  J. Simpson Africa.  1883.  History of Huntingdon and Blair Counties, Pennsylvania.  L.H. Everts, Philadelphia. Biographical sketch of our subject's son, Abraham CORBIN.  (See link for extended excerpt.) 

William CORBIN, also a native of Maryland, settled on the Raystown branch, on a farm which had been improved before the Revolution by a man named PRIDMORE.  CORBIN died on that place some time about 1820.  He was the father of sons named William, David, John, and Abraham and of a daughter who became the wife of Reading BYE...  William CORBIN, a descendant of an old Maryland family, moved from near Hagerstown, Md., to Huntingdon county before 1800.  Soon afterwards he settled upon the farm in Juniata township now owned by William E. CORBIN...

9.  U.S. Geological Survey.  GNIS:  Geographic Names Information Service (online database).  The Raystown Branch flows north out of Fulton County, though eastern Hopewell, Lincoln, Penn, and Juniata Twps.  A dam south of Huntingdon has created a major lake, called Raystown Lake.  Downstream from the dam, the Raystown Branch joins the Juniata River.

10.  Broderbund.  World Family Trees.  Vol. 40, Pedigree #356.

11.  Email from Tom Brown (11 Oct 2000).