Daily AncestorR1
R1 after a house number in the 1900 census marks the second house on the same lot, standing in the rear; R2 is the third.
The 1900 instructions dealt with lots that held more than one house. The front house kept its street number. The second house, behind it, got the same number with R1 added, the third got R2, and so on.
So 412 R1 is not a typo for a room or an apartment. It tells you the family lived in a rear house at 412, which helps when you look for the spot on a city map or in a directory.
As seen in a recordStreet and house number columns of the 1900 census
Elm St., 412 R1, Bracken, Lyle, Head
How to cite this page
Daily Ancestor. "R1." Dictionary of Old Record Words. https://dailyancestor.com/dictionary/abbreviations/census-r1. Last checked 2026-10-12.