The "Steavinson" 1990 census contains more than one riddle.
2521 Perot does not exist and never did. Perot Street runs east/west and stops at 25th Street. It has no 2500 block of houses. When you reach the intersection of Perot and 25th, you can turn left and walk about 50 feet and reach the 2500 block of Olive Street. If you turn right, you walk about 100 feet and you reach the 2500 block of Meredith Street.
The census taker switched Perot for Olive. The top of the page on which John Stephenson appears contains houses from the 2500 block of Meredith so our census taker didn't make that mistake. If you look at the intersection on Google Maps, you can see that Perot and Olive are not far off-line from each other, and he may have thought Olive ended and Perot continued. Ordinarily we would never know because in the construction of a new building, most of the 2500 block of Olive Street was demolished. But Mary Spearing Stephenson died at 2512 Olive Street in 1908. And John died at 2518 Meredith in 1924. Walk up 25th Street to Aspen, turn left and walk another block and you reach Richard and Rose Stephenson's house at 2615 Aspen Street.
So now we can confirm ...
1. The 1900 census entry is for John and Mary Spearing Stephenson, Sr.
2. The correct address is 2521 Olive Street, where Mary would die eight years later.
3. The Stephensons had seven children - four survived, two died and one is unaccounted for.
4. The 1900 census entry that John was born in May 1845 may be the most reliable.
At this point, it seems to me that the only thing missing are facts concerning John and Mary's immigration. We have basis to believe he arrived in 1866 from Ireland, and that she arrived from Ireland but we don't have a date. Nor do we have a port of entry. I believe I saw an naturalization for John. It may be part of the Ancestry Stephenson tree. But the naturalization papers I've seen from that era merely contain the affirmation of the applicant to be naturalized. I haven't seen an application that contains details. Do you know of a source in the immigration process circa 1866 that would capture details? As you may have seen, I am now working with the Irish Spearing/Sparing family forum. That provokes another interesting question. Either Radcliff or Heywood pointed out that Stephenson is not a common name in Limerick but has been there for 300 years. Apparently Spearing/Sparing is very common. What if John and Mary knew each other from Limerick? They were just under two years apart in age. Finding one in Limerick might target where to look for the other. According to the 1900 census, they were married in 1870. He was age 25 and she was age 23. Sounds right.
Again, thanks for all your interest, help and guidance in piecing together this puzzle.
Mark
With whatever we get from that, it looks like its time to virtually visit Newcastle West. Thoughts?