"STROUP" is an Anglicized surname.  The original surname is most likely STRAUB, but could be some other Germanic surname that is phonetically similar (e.g., STRUB or STROOP).

1.  Marriage Record:

2.  1860 Census Every-Name-Index/Images (online at Ancestry.com, Image #12 of 37):  Fond du Lac P.O., City of Fond du Lac (Ward 4), Fond du Lac Co., WI, Roll M653_1408, p. 593, PN 99, 738/715, enumerated 22 Jun 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):¤•

George Stroup	32	M		Rag Peddler		800	Germany
Catharine "	23	F					"
Louisa    "	2	F					Wis

3.  1870 Census Every-Name-Index/Images (online at Ancestry.com, Image #54 of 80):  Fond du Lac P.O., City of Fond du Lac (Ward 3), Fond du Lac Co., WI, Roll M593_1713, p. 274A, PN 54, 449/423, enumerated 30 Jun 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):¤•

Troop George	39	M	W	Pedlar			Germany
_____ Catharine	34	F	W	K H			Do
_____ Louisa	12	F	W				Wisconsin
_____ Willis	9	M	W				Do
_____ George	7	M	W				Do
_____ Ada	5	F	W	at home			Do
_____ Nicholas	3	M	W				Do

4.  1880 Census Every-Name-Index/Images (online at Ancestry.com, Image #17 of 40):  13 Waupun Street, City of Fond du Lac (Ward 3), Fond du Lac Co., WI, Roll T9_1425, p. 206A, PN 17, SD 1, ED 41, enumerated 5 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

10

13

21

24

25

26

*

13

164

178

Straap George

W

M

50

/

Buying old Rags

Hessen Darmstadt

Hessen Darmstadt

Hessen Darmstadt

"   Mary C

W

F

43

Wife

/

Keeping House

Prussia

Prussia

Prussia

"   William

W

M

19

Son

/

Works in Saw Mill

Wis

"

"

"   Geo

W

M

17

Son

"    "   "   "

"

"

"

"   Edward

W

M

15

Son

"    "   "   "

"

"

"

"   Nicholas

W

M

12

Son

Attends School

/

"

"

"

"   Emiel

W

M

9

Son

"       "

/

"

"

"

"   Anna

W

F

5

Dau

at Home

"

"

"

"   Benjamin

W

M

2

Son

"

"

"

*Waupun Street

5.  1890 Census:  the 1890 Census Population Schedules were destroyed.

6.  1900 Census Every-Name-Index/Images (online at Ancestry.com, Image #16 of 32 — indexed "Stump"):  114 Waupun [St.], Fond du Lac City (Ward 3), Fond du Lac Co., WI, Roll T623_1788 (Book 2), p. 174B, SN 8, SD 3, ED 25, enumerated 6 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):¤•

1900:  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	7	8	9	11	12	13	14	15	19	20	22	23	24	25	26	27
*	114	159	165	Stroup Mary C	Head	W	F	Sep 1836	63	Wd	11	8	Ger	Ger	Ger			Y	Y	Y	O	F	H
				"   Annie M	Dau	W	F	Jun 1875	24	S			WI	Ger	Ger	??? ???	0	Y	Y	Y
				"   Benj	Son	W	M	Feb 1878	22	S			WI	Ger	Ger	Tailor	0	Y	Y	Y
*Waupun

7.  1910 Census Index/Images (online at Ancestry.com, Image #12 of 28):  14 North Waupun Street, Fond du Lac City (Ward 2), Fond du Lac Co., WI, Roll T624_1712 (Part 1), p. 75B, SN 6B, SD 5, ED 48, enumerated 30 Apr 1910, official enumeration date 15 Apr 1910 (extracted by Diana Gale Matthiesen):¤•

1910:  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	7	8	9	10	11	12	13	14	15	17	18	19	20	21	22	23	24	26	27	28
*	14	144	145	Barhyte John K	Head	M	W	33	M1	6			WI	NY	Eng Eng		Eng	Line Man	Telephone	W	N	8	Y	Y	O	M	H
				_______ Anna M	Wife	F	W	35	M1	6	1	0	WI	Ger Ger	Ger Ger		Eng	None					Y	Y
				Stroup Catherine	Mother in law	F	W	73	Wd		11	8	Ger Ger	Ger Ger	Ger Ger	1853	Eng	Own Income					Y	Y
*North Waupun Street

This record was difficult to read, so my extraction may not be entirely accurate.

8.  1910 Census Index/Images (online at Ancestry.com):  not found.