1.  Marriage Record:

2.  1840 Census Index and Digital Images (online at Ancestry.com; Image #25-26 of 40; extracted by Diana Gale Matthiesen):

1840

IN

Wayne Co.

Germantown

p. 315

Micheal Jonsombaugh

100 010 - 000 010

0001000

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	4 or under	1835-1840	= Henry (b. 1839/40)
1 male	20-29	1810-1820	= Michael (b. 1814/5)
1 female	20-29	1810-1820	= Elizabeth (b. 1816/7)
1	person engaged in manufactures and trades

3.  Census Microfilm Records:  Indiana, 1850 (Broderbund CD-302):  Cambridge City, Wayne Co., IN, p. 19B, 268/268, enumerated 28 Aug 1850 (extracted by Diana Gale Matthiesen):

Michael Johnsonbaugh	35	M	Merchant	1000	Pennsylvania
Elizabeth Johnsonbaugh	33	F			"
Henry Johnsonbaugh	10	M			Indiana
George Johnsonbaugh	9	M			"
Ann E. Johnsonbaugh	5	F			"
Eve Johnsonbaugh	67	F			Pennsylvania

Eve is almost certainly Michael's mother.

4.  Andrew W. Young.  1872.  History of Wayne County, Indiana, from Its First Settlement to the Present Time.  Robert Clarke & Co., Cincinnati (online at GenealogyLibrary.com).  On p. 140:

POST-OFFICES AND POSTMASTERS... Cambridge... Michael Johnsonbaugh, March 16, 1849...

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