I was searching the 1900 census at Ancestry.com for the Joseph Watson mentioned in an earlier blog post as having naturalized in 1900 in Cook County, Illinois.
The search as indicated in the image above is not the way I should search if all I know about Joseph is what is on his card. Joseph's naturalization index card indicated he lived at 2539 117th Street in Chicago when he was naturalized and that he naturalized on 5 November 1900.
As mentioned earlier, searching for Joseph in Chicago is reasonable given the proximity of the census date and the naturalization date--but if he is not located in the City of Chicago, I would expand my search to all of Cook County and work from there.
Using only the index card, and nothing else, we don't know that Joseph was born in England. The card indicates that the country to whom he owed allegiance was "Gt. Britain Ireland." Our search should include not just England, if we're basing our search terms on the details contained in the index card. We may very well miss out on Joseph if we only search for natives of England.
[It turns out that this Joseph was born in England, but that's not stated on the index card.]