Co. Roscommon incorporated the following Mayo & Galway townlands around 1895:
Mayo: Ardkill, Attiantaggart, Ballaghadeereen, Ballymaging or Castlemore, Ballyoughter, Barnboy, Bockagh, Bogtaduff, Bohalas, Boleysillagh, Brogher, Calveagh Upper & Lower, Cashelard, Cashelcolaun, Cloonavullaun, Cloonlumney, Cloonmeen, Coolaghtane, Coollena, Creggan, Cross North & South, Crunaun, Currunagh, Derrynacross, Derrynagur, Derrynanaff, Doogary, Drumacoo, Druminalassan, Fallsollus, Frasnadeffa, Friarshill, Glebe, Gortanure, Hawksford, Ishlaun, Islandmore, Largan, Kilcolman, Kilkeeran, Killadangan, Kilvanloon, Knockanaconny, Lung, Magheraboy, Poolboy, Toobrackan, Toomanagh, Tullaghanmore or Edmonstown Demense, and Tullaghanrock.
Galway: Bracklin, Carrowkeel, Carrownaglogh, Cartron, Coolroghaun, Cornaveagh, Deerhippoo, Dunamon, Garraun North & South, Kilbegnet, Lisduff, Oughtagh, Rosmoylan, Shanballyeden, Tonamaddy.
Before 1st May 1654, under the Act of 1653 by order of the Commissioners of the Parliament of England for the Affairs of Ireland, dated 14th October 1653, all persons having the right to favour and mercy were to remove and transplant themselves into the provence of Connacht and Co. Clare.
This era was known as the Transplantation of Connacht resulting in many families loosing their land in their native county. Many Baronies within the county changed size and shape over time up to 1898. Townlands too were swapped between parishes as a means to pay tithes - if one parish was not as affluent as another.
source: Roscommon Family History Society.