I believe we are related.I checked the 1880 IA census and found Adolph with his mother Maggie, sister Clara and brother Edwin.I backtracked through the census records.
1870 Carroll Co., IA
John W. Hollenbeck, age 31, b. IL
1860 Shell Rock, Butler Co., IA
David Hollenbeck, age 40, born IN
Emeretta Hollenbeck 38
John W. Hollenbeck, age 20 (b. IN)
Sarah Hollenbeck, age 14
Henry Hollenbeck, age 10
Martin L. Hollenbeck, age 8
William L. Hollenbeck, age 5
Emily J. Hollenbeck, age 3
R. Isabell Hollenbeck, age 1
A Family Tree on Ancestry gave me a marriage date of 20 Jan 1839 in Marshall Creek, Clark Co., IL for David Hollenbeck and Emeretta Laughter
1856 IA Census, Iowa City, Johnson Co.
David Hollenbeck, age 36, b. IN
Emretta Hollenbeck, age 33, b. IN
John W. Hollenbeck, age 16, b. IN
Henry D. Hollenbeck, age 6
Sarah Hollenbeck, age 10
Martin L. Hollenbeck, age 3
William Hollenbeck, age 1
1850 Linn County, IA
David Hollenbeck, age 31
Emeretta Hollenbeck, age 27
John W. Hollenbeck, age 10
Mary J. Hollenbeck, age 9
Sarah Hollenbeck, age 4
Andrew D. Hollenbeck, age 1
The same Family Tree states that John Wesley Hollenbeck died 22 Feb 1884, I assume in IA.
David Hollenbeck was born 21 Nov 1819 in Scott Co., IN and died 9 Dec 1893, Vinton, Benton Co., IA.
David's parents were John Hollenbeck (born Albany, NY) and Rhoda Henderson and this John Hollenbeck's parents were Jacob Hollenbeck and Helena VanWie.
When I saw the Scott County, IN connection I knew there had to be a relation between your Adolph and my Henry Hollenbeck.David Hollenbeck, Adolph's grandfather, was a first cousin to my Henry Hollenbeck.
My 3rd great-grandfather was Peter Hollenbeck and he and the second John Hollenbeck, father of David, were brothers.Peter, along with his father Jacob and brother John and other siblings, moved from the Greene/Albany/Coxsackie area of NY to Scott County, Indiana around 1817. Peter was married to his first wife in Scott County and they moved to Jackson County, IN where my Henry Hollenbeck was born in 1835; Peter eventually moved to IA, Keokuk, and various other places; Henry moved to Kansas in 1859 and Peter followed about 1865.
Hope this helps.Let me know if you have any questions.