Hi, If you go to the nationalarchives site, then click on Browse census, then you can check all of Dublin to see if there's a Back Brook listed. As far as I know, only Donnybrook existed at census times-1911. Bonnybrook + Rockbrook are fairly new. Maggie
There is mention of Rockbrook in the Dublin County List of Landowners (1 acre or over) 1873 - 1875 (see IGP Archives), so Margaret I think it should be in 1901 and 1911 Census. However, it was only a thought (i.e. transcription error suggestion). Joyce