1.  Census Index:  U.S. Selected Counties, 1820 (Broderbund CD-314):  not found.

2.  Census Index:  U.S. Selected Counties, 1830 (Broderbund CD-315):

1830

Sampson, Benjamin

PA

Washington Co.

East Finly Twp

p. 328

3.  Census Index:  U.S. Selected Counties, 1840 (Broderbund CD-316):

1840

Sampson, Benj.

PA

Washington Co.

E Findley Twp

p. 173

4.  1850 Census Index/Microfilm (online at GenealogyLibrary.com):  East Finley Twp., Washington Co., PA, p. 541B, 80/80, enumerated 24 Oct 1850 (extracted by Diana Gale Matthiesen):

Benjamin Sampson	46	M	Farmer	1000	Md
Rissia      "	42	F			Pa
Thomas      "	19	M	"		"
Sarah A     "	16	F			"
Rachel      "	14	F			"
Martha J    "	12	F			"
Jacob       "	9	M			"
Albert      "	7	M			"
Jemima      "	4	F			"

Benjamin's wife's name is very hard to read, but the first letter is definitely "R," not "M," so her name would not appear to be Melissa (see below).  "Rissia" is almost certainly a nickname, but for what?

5.  Descendants of David Sampson by Scott A. Sampson.  Has Benjamin's wife's given name as Melissa.

7.  Broderbund.  World Family Trees.  Vol. 9, Pedigree No. 2824.