WARNING:  Margaret may be his daughter, not his wife.

1.  Census Microfilm Records:  Pennsylvania, 1850 (Broderbund CD-305):  Bellefonte, Centre Co., PA, p. 164B, 102/120, enumerated 31 Jul 1850 (extracted by Diana Gale Matthiesen):

Henry Brockerhoff	51	M	Merchant	40,000	Germany
Margaret Brockerhoff	20	F			Ireland
James Mullin	20	M	Clerk		Do
James Kinney	45	M	Gardner		Do
Mary Brenigan	23	F			Do
Elisabeth McAllister	24	F			Do
Fanny Atherton	24	F			England
L D Straub	22	M	Merchant		Penna
Wilson L Rothrock	21	M	Clerk		Do

Had Margaret not been born in Ireland, I would have pegged her for Henry's daughter.  If she is his wife, they must have recently married because she has had no children.  Of course, it's always possible that Henry lived in Ireland for a time, before coming to America, in which case Margaret is his daughter.

2.  Hans Pettelkau.  Forschung Brockerhoff.[link died]