I've never seen "United States" as a given name, but here it is on a birth record from 1909- for father and son.
|Birth certificate for United States Cook, Jr.|
Born May 29, 1909 in Newark, Essex County, New Jersey
Father: United States Cook. Mother: Bertha Wilkins.
I also found it unusual that the notice of a name change- over sixty years later- was on the microfilm with the birth certificate.
In case you thought this was a clerical error, it's not. Here is United States Junior with his mother in the 1920 census.