Patti
I see that your Osterloh family came from Hude Parish in Oldenburg, and Johann Haverkamp was one of the ancestors. I have Haverkamps and Osterlohs in my ancestry and have done some research on them in this parish.
The Haverkamp family came from the town of Lintel in Hude Parish, and I have considerable information on it, if you are interested. If the connection can be made to it (which should be possible throught the Kirchenbuch (church register), the family can be traced back into the 1400's through it original home, using Janssen-Holdiek's study of Lintel, which traces each residence in the community back to its earliest documented appearance, and beyond (using archaeological excavations) to its earliest days. I have translated some of the book and can share it with you in English.
The name Johann Haverkamp, of course, was quite common, but among those who held it was the mayor of Hude at the time of the French Occupation during the Napoleonic Wars. I believe he died in the 1840's or so.
The Osterloh family originated at Immer-bei-Ganderkesee (near Bremen) on the edge of the Stüher Forest; the original farm has been owned and operated by the same family since 1493, when the progenitor of the family, Hinrik Osterloe, acquired the heavily indebted "Eggerdes Bouw." Where he came from is not known. The current owner of the property is Dieter Osterloh.
This farm is honored as the Stammhof (original home) of today's entire Osterloh clan. From here the family spread out, to the neighboring districts of Ganderkesee (1509), Kimmen (1521), Iserloy (1550), Grüppenbühren (1567), Burstel (1598), Klattenhof (1601), and in later years in Holskamp, Hengsterholz, Elmeloh, Almsloh, and Schlutter (from which the Lintel Osterlohs came).
This information came from a newspaper clipping (Delmenhorster Kurier, 7/12/1993) celebrating the 500th anniversary of family ownership.
Hugo Schroeder