Sounds like the same Cronk's it's actually for one of my mom's church friends. I've been trying to help her. I actually believe that I found the father of yours and her John Cronk. I found no Cronk's or at least any version of the name I could believe. There's a lot of people that say he came from Kronkite's and others. However from my studying, I do not believe that.
John Cronk told the census worker in 1880 that his father was born in Germany, while I believe he or the census worker could have been mistaken as to where exactly John was born, I do not believe that they could have somehow got the birthplace of his father wrong since it was in a completely different country.
Taking that info and adding the years that his father had to have been born to have fathered John (reasonably that is) his father would have had to come to america before 1827. He could have been anywhere from 18-45 or 50 to have fathered him. That means a birthday somewhere between 1780+/- to 1808+/-.
When people immigrated that late, while in some instances I could see their names radically changing mainly they just took on the spelling of their name that the ships personel or immigration people wrote on whatever official document.
Therefore Kroncke was the only germanic name that I could buy as being the possible original spelling of the name.
I could not find ANY Cronk or Kroncke's immigrating to the US in the timeframe I noted above. I did find however, a family of Cronk's John Sr. Abigail and John Jr. Cronk who immigrated to Ontario Canada in 1801.
John Cronk born in NY, at least some of his family was also in Michigan. Michigan is just across the lake from Ontario.
I don't know exactly how yet, but i would be willing to bet that the Cronk family who immigrated to Ontario is where your Cronk family came from.
While there are a lot of Cronk families in NY to choose from that might be possibilities, you can't escape the fact that John said his father was born in Germany. All the possible Cronk families in NY had already been established there for at least 2-3+ generations. Therefore it couldn't have been them.
Hope this helps,
P.S. She was supposed to go to the library with the info I gave her and get back to me. I will let you know when she does.
You can email me at firstname.lastname@example.org