In the 1870 census there is a John H. Groat in Brookfield Twp, Clinton Co. IA. He is 39 from NY married to Elizabeth (38) from OH.They have several children including a James, age 13, b. in IA.They also have an older son Rufus, 18, b.in IA. Another individual lives with the family, a Sammuel Brook(s), also 18 and b. in OH.
In 1880 John and Elizabeth are in Wheeler Twp., Sac Co., IA.S. Brooks is ennumerated with them as stepson.Also in 1880 James and Sammuel are both listed as borders in the household of a man named Schaefer in Eden Twp, Sac Co., IA.
In 1885 IA State Census, John is in Carroll Twp. Carroll Co. IA.In the 1885 NE State Census, James is listed with wife, Hattie(23), and dau. Ethel(2) in Milford Twp., Seward Co. Directly following this listing is one for Rufus Groat and wife Josephine and family.
In 1900 James and famlily are in South Branch Twp., Pierce Co., NE.Rufus is in Allen Twp., Pierce Co., NE.
In 1910 both families are in SD.
In 1920 James and family moved yet again to Valentine Twp., Cherry Co., NE.
In 1930 Harriet is widdowed and living with dau. Ethel and son-in-law William Moore in Osmond Twp., Pierce Co., NE.
Going further back to John's roots. In 1860 John(29), Elizabeth and their children: Belden(5), Louda(3), James(1)and Sammuel Brooks(8) are in Madison Twp., Jones Co., IA which is right next to Jackson Co. where James was supposed to have been born. The household listed right after this one belongs to A.J. Groat(27) also from NY with wife, Nancy (18), also from OH.
In 1850 there is a Peter H. "Grant" (Groat)(54)b. NY living in Monmouth Twp., Jackson Co., IA.He has several sons including John (20) b. NY and Andrew (18) b. NY.
I think these are pretty reasonable family connections.They can probably be shored up with some obits, marriage records or whatnot.Let me know if you have any trouble tracking down the specific ennumerations.