His obituaries comes from unknown sources and were collected by my mother. Both list his birthplace as Elk Point, SD, which is in Union County. The source is probably my mother who was his oldest child. His death record has no info on his birth place.
The funeral card my mom has also lists Elk Point as his birthplace. Again my mom was probably the source of the info.
There is an on-line database, South Dakota Births, 1856-1903, at ancestry.com. His entry there lists Union Co., SD as his birthplace. I need to locate the source of that database to evaluate the information given. He filed a delayed certificate of birth in 1961 when he turned 65 so he could collect Social Security. On that the city is left blank but it lists Union Co., SD as the birth county.
All of the US and SD census records for him from 1900 to 1945, list South Dakota as his birthplace, as does the copy of the Nebraska marriage register I have. So far so good. Everything points to Elk Point, Union Co., SD as his birthplace.
However, on his WWI draft registration card, it has Clay Co., So Dak as his birthplace.
And his SS-5 Social Security application lists his birthplace as Elk Point, Clay Co., SD. That's odd because there is no Elk Point in Clay County. The application is from 1952, several years before he filed the delayed certificate of birth.
On the 1945 SD Census records for himself, his birthplace is just SD. On all of his children's cards in the same handwriting on each one that is different from the one on his, the father's birthplace is Elk Point, Spink Co., SD. There is no Elk Point in Spink Co., SD, either. I have no idea who the informant was for that info, probably my grandmother filling out the cards for all the children.
So where does that leave us? My conclusion is that he was born in or near Elk Point, Union Co., SD. For several decades he probably thought Elk Point was in Clay Co. He probably figured out his error when he was gathering information for his delayed certificate of birth. Clay Co. is due west of Union Co. The Spink Co. error is possible because my grandmother was born in Illinois and lived in northwest Nebraska. She was not familiar with the geography of southeast SD. Spink Co. is way north of Union Co.
Other sources I can try to locate that might give more information are land records that show where his parents were in 1896, county directories from that time period, newspapers from around Elk Point that might have carried a birth announcement. I also need to get my grandparents's Sheridan Co., NE marriage license to see what info it has on it.
If I was conclusion-based, I'd enter my conclusion in my genealogy software and use his delayed certificate of birth as the source. If I was evidence-based, I'd put in all these sources with alternate facts and mark my conclusion as the primary fact. If I was organized I'd make a choice and actually enter the information into the database one way or the other.