1.  Marriage Record:

2.  1790 Census Index/Images (online at Ancestry.com; Image #41 of 51; extracted by Diana Gale Matthiesen):¤

1790

PA

Northumberland [now Snyder] Co.

p. 81

Ln. 21

Charles Stroup Junr

1-0-3-0-0

These data indicate:

Gender and Type	Age Class	Therefore Born	Individuals Inferred
1 free white males	16 or over	in or bef. 1774	= Charles
3 free white females	all ages	in or bef. 1790	= Elizabeth = Daughter A = Daughter B

3.  Census Index:  U.S. Selected Counties, 1800 (Broderbund CD-312):  not found.

4.  Charles A. Fisher.  1938.  Snyder County Pioneers.  Self-published, Selinsgrove, PA (reprinted 1991 by Genealogical Publ. Co., Baltimore, MD).  On p. 90:

Charles STRAUB, Junior, was assessed in Penn Township for the first time in 1787, and in that year was designated as a single freeman.  In [the] 1790 [census], he was married, and he and his wife had two daughters.  In 1796, when Mahantango township was formed, he was assessed there.  It is supposed that he was a son of Charles, Senior, who came to Penn Township before 1790.

If Charles came of age (21) in 1787, then he was born 1765/6.  Fisher was prone to making suppositions that everyone picks up and takes as fact:  Charles "Junior" could just as easily have been Charles Senior's nephew as his son — or not related, at all.

5.  Herbert C. Bell.  1891.  History of Northumberland County...  Brown, Runk & Co., Chicago (text online at the PAGenWeb Northumberland Co. web site [link died]).  Paraphrased by DGM:

Mahantango Twp. was formed in 1795 from Penn's Twp.  In 1816, Mahantango Twp. ceded land to Perry Twp. and, in 1818, to Washington Twp., at which point Mahantango ceased to exist.  Perry and Washington Twps. were further subdivided to form West Perry, Chapman, and Union Twps.  These five townships were among those ceded by Union Co. to form Snyder Co. in 1855.  Therefore, individuals living in "Mahantango Twp., Northumberland Co." were actually living in what later became south-central and south-eastern Snyder Co.

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