1.  Marriage Record:

2.  1790 Census Index and Digital Images (online at Ancestry.com; Image #13 of 17; extracted by Diana Gale Matthiesen):¤•

1790

PA

Mifflin Co.

p. 124

Ln. 16

Wm Frampton

1-1-6-0-0

These data indicate:

Gender and Type	Age Class	Therefore Born	Individuals Inferred
1 free white male	16 or over	in or bef. 1774	= William (b. 1744)
1 free white male	15 or under	1774-1790	= David? (b. 1770)
6 free white females	all ages	in or bef. 1790	= Sarah (b. 1755) Five of the following six: = Nancy (b. 1776) = Susanna (b. 1782) = Eleanor (b. ca. 1784) = Sarah (b. 1785) = Anna (b. ca. 1786) = Mary (b. ca. 1789)

Was Mary born after 1790?  Listed three lines from Sarah's sister, Christiana (STEELY) STROUP, wife of George STROUP, who is two lines from Jno. FRAMPTON, who is 13 lines from Philip STROUP, husband of William's daughter, Margaret, and brother of George. 

3.  1800 Census Index and Digital Images (online at Ancestry.com; Image #16 of 27; extracted by Diana Gale Matthiesen):¤•

1800

PA

Mifflin Co.

Derry Twp.

p. 494

Ln. 41

Frampton Wm

10110-20010-00

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	9 or under	1790-1800	=
1 male	16-25	1774-1784	=
1 male	26-44	1755-1774	= William (b. 1744?)
2 females	9 or under	1790-1800	=  =
1 female	26-44	1755-1774	= Sarah (b. 1755)

List was roughly alphabetized, so no neighborhood reconstruction is possible.  The only other FRAMPTON in the township is John (æ 45+), who is presumably William's father.

4.  1810 Census Index and Digital Images (online at Ancestry.com; Image #5 of 5; extracted by Diana Gale Matthiesen):¤•

1810

PA

Mifflin Co.

Derry Twp.

p. 1029

Ln. 18

Wm. Frampton

01111-01201-00

25 35 0 0 3 19 6 18 1 0 0

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	10-15	1794-1800	=
1 male	16-25	1784-1794	= Son
1 male	26-44	1765-1784	= David (b. 1770)
1 male	45 or over	in or bef. 1765	= William (b. 1744)
1 female	10-15	1794-1800	=
2 females	16-25	1784-1794	= Mary (b. ca. 1789) = Anna (b. 1786)
1 female	45 or over	in or bef. 1765	= Sarah (b. 1755)
25 yds	Woollen Cloth
35 yds	Flaxen Cloth
0 yds	Cotton Cloth
0 yds	Hempen Cloth
3	Spinning Wheels
19	Common Sheep
6	Horses
18	Cattle
1	Looms
0	Hand Cards
0	Sugar

Listed next to son, David FRAMPTON, who is 14 lines from Susanah (STROUP) STEELEY, widow of Lazarus. 

5.  1820 Census Index and Digital Images (online at Ancestry.com; Image #2 of 7; extracted by Diana Gale Matthiesen):

1820

PA

Armstrong [now Clarion] Co.

Redbank Twp.

p. 276

Frampton William

100101-00101-0-100

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	9 or under	1810-1820	=
1 male	19-25*	1794-1801	=
1 male	45 or over	in or bef. 1775	= William (b. 1744)
1 female	16-25	1794-1804	=
1 female	45 or over	in or bef. 1775	= Sarah (b. 1755)
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 three lines from their son, David FRAMPTON.

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

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