1.  Marriage Record:

2.  1840 Census Index and Digital Images (online at Ancestry.com; Image #15-16 of 34; extracted by Diana Gale Matthiesen):

1840

PA

Centre Co.

Harris Twp.

p. pp. 128B-129A

Jacob Johnstonbaugh

000 010 - 100 010

0100000

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	20-29	1810-1820	= Jacob (b. 1815)
1 female	4 or under	1835-1840	= Margaret (b. 1839)
1 female	20-29	1810-1820	= Mary (b. 1818/9)
1	person engaged in agriculture

Listed one line below Jacob's brother, Thomas JOHNSTONBAUGH, and seven lines above their brother, George Washington JOHNSONBAUGH. 

3a.  AIS Mortality Schedules Index (online at Ancestry.com):

Year	Surname	Given Names(s)	County	State	Age	Sex	Month of Death	State of Birth	Cause of Death	Occupation	ID#
1850	JOHNSONBACH	MARY	CENTRE	PA	31	F	MAY	PA	UNKNOWN	NONE LISTED	MRT43_8835

3b.  1850 Census Index/Microfilm (online at GenealogyLibrary.com):  Harris Twp., Centre Co., PA, p. 115A, 1356/1479, enumerated 7? Nov 1850 (extracted by Diana Gale Matthiesen):

Jacob Johnsonbach	35	M	Farmer
Thomas     "	8	M
William    "	6	M
Jane       "	4	F
Jane Glense?	43	F

This enumerator left the birth location blank for everyone on the page, except the first person on the page, with the implication that everyone on the page was born in PA.  Probably a safe assumption.

4.  1860 Census Images (online at Ancestry.com; Image #2-3 of 48):  Boalsburg P.O., Harris Twp., Centre Co., PA, pp. 552-553, PN 98-99, 715/737, enumerated 30 Jul 1860 (extracted by Diana Gale Matthiesen):

Jacob Jonsonbaugh	45	M		Farmer	1000	875	Penna
Nancy      "	29	F					"
Thomas     "	18	M		Farm Laborer			"
William    "	16	M		Farm Laborer			"
[next page]
Jane A. Jonsonbaugh	14	F					Penna
John       "	8	M					"
Kate       "	6	F					"
Mary E     "	5	F					"
Benjamin   "	3	M					"
Anna       "	1	F					"
Jacob H Myers	19	M		Farm Laborer			"

Some secondary sources have mistakenly listed Nancy as Jacob's daughter; she is not, if for no other reason than that Jacob & Mary were too young to have been her parents.  Thomas, William, and Jane are Jacob's children with Mary; the rest are his children with Nancy.  Listed eight households below Jacob's brother, George Washington JOHNSONBAUGH. 

5.  1870 Census.

6a.  1880 Census Every-Name-Index/Images (online at Ancestry.com, Image #6 of 16):  Patton Twp., Centre Co., PA, Roll T9_1112, p. 282B, PN 6, SD 7, ED 229, enumerated 4 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

11

13

21

24

25

26

48

49

Johnsonbaugh Nancy

W

F

52

/

Keeping house

PA

PA

PA

____________ John W

W

M

28

Son

/

Farm Laborer

PA

PA

PA

____________ Margaret

W

F

15

Dau

/

/

PA

PA

PA

____________ David

W

M

14

Son

/

Farm Laborer

PA

PA

PA

Listed two households from son B.F. JOHNSONBAUGH (see next source).

6b.  1880 Census Every-Name-Index/Images (online at Ancestry.com, Image #6 of 16):  Patton Twp., Centre Co., PA, Roll T9_1112, p. 282B, PN 6, SD 7, ED 229, enumerated 4 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

11

13

21

24

25

26

47

47

Tate William E

W

M

35

/

Farmer

PA

PA

PA

____ Elizabeth

W

F

65

Mother

/

Keeping house

PA

PA

PA

Farber Elizabeth

W

F

22

Niece

/

Servant

PA

PA

PA

Wason Agnus

W

F

30

Servant

/

Servant

PA

PA

PA

Johnsonbaugh B F

W

M

24

Servant

/

Farm Laborer

PA

PA

PA

Patterson William

W

M

14

Servant

/

Farm Laborer

/

PA

PA

PA

7.  Broderbund.  World Family Trees.  Vol. 6, Pedigree #2310.