In attempting to find a definitive answer to the question as to why some authorities refer to the townland of Corkhill as Corkill, in County Tyrone, I asked Mr. Ed Redmond of the U. S. Library of Congress some questions. I think his answer would be of benefit to the list, as another source of information: "According to "General Index to the Town and Townlands of Ireland, (Registrar-General of Ireland" (Dublin, 1861, reprinted 1984 - http://lccn.loc.gov/83082450), there were five locations in County Tyrone, Ireland at the time of the 1861 publication... With regard to an authoritative spelling of Corkhill, we suggest consulting the Placenames Database of Ireland which facilitates the standardization of "Irish Placenames" that have been approved by the [Ordnance Survey of Northern Ireland]... The web site may be accessed via <http://www.logainm.ie/Do.aspx?uiLang=en. " This later site is very handy, but it may require some diligent searching on your part. For example, under Corkhill (of County Tyrone) there were four citations but none of them came up with the one that I was looking for. Further down the list I located the Irish spelt name of Corrchoill, which was what I was looking for. This data base contains both the Irish and English spellings for: 61,622 townlands 18,311 streets 6,180 minor features 3,515 electoral districts 2,925 post offices 2,574 civil parishes 679 rivers 651 lakes 374 features 345 baronies 268 towns 219 population centres 211 islands and archipelagos 190 mountains and mountain ranges 148 monuments 121 promontories 105 bridges 104 bays 83 hills 62 localities 32 counties 32 rocks 26 passes 25 valleys 19 strands 17 estuaries 12 fields 61 other geographical units Regards, Jim Carroll