The Anglo-Irish war, an Cogadh Angla-Éireannach or in better Irish Cogadh na Saoirse, has made certain place-names famous. I guess many people would like to know those names in Irish. This is my best attempt, using the logainm.ie website as my primary source.
To start with, Soloheadbeg. It should be written Sulchóid Bheag without the article, and the genitive form is Shulchóid Bheag (i.e. I guess I must stop writing *an tSulchóid Bheag, *na Sulchóide Bige).
Then Knocklong. That would be Cnoc Loinge.
Then Rinneen: An Rinnín.
Followed by Tooreen or Toureen: An Tuairín.
Ballinalee is in Irish Béal Átha na Lao.
Balbriggan is Baile Brigín.
Kilmichael – now that is a name you should know. In Irish, Cill Mhíchíl.
Kilbrittain is Cill Briotáin.
Pickardstown in County Waterford is Baile an Phiocardaigh.
Clonfin or Cloonfin is Cluain Fionn.
Dromkeen is Drom Caoin.
Upton in Co. Cork is Garraí Thancaird.
Clonmult is Cluain Molt.
Coolavokig is Cúil an Bhuacaigh – that -ig in the English name is due to the fact that a final -igh is an [ig] in Munster.
Sheemore in Co. Leitrim is an tSí Mhór, and the genitive case is na Sí Móire, if you ask me.
Cloonbannin is Cluain Báinín.
Selton Hill I cannot find. Probably it is connected with Sailtean, i.e. Seltan in Leitrim.
Burgery is Burgáiste, and Burgatia is the feminine an Bhuirgéiseach (genitive: na Buirgéisí).
Crossbarry is Crois an Bharraigh. (Note that Crois is here in a frozen dative case. For a similar reason, Corcaigh is Corcaigh and not Corcach.)
Headford or Headfort near Killarney is Lios na gCeann (some other Headfords are called Áth Cinn, but this one is Lios na gCeann).
Scramoge in Roscommon is Scramóg, genitive Scramóige.
Kilmeena in Mayo near Westport (Cathair na Mart) is Cill Mhíona.
Carrowkennedy (in Mayo too) is Ceathrú Chinnéide.
Coolacrease in Offaly is Cúil an Chraois.
Some placenames I haven’t been able to trace, because it still happens that a placename in history books or in the English-language Wikipedia is so garbled that logainm.ie does not recognize it. This is another sad consequence of Ireland’s anglicization. Let’s keep Irish alive together and see to it it will never again be threatened by extinction. Learn the language, read the books, teach yourself the folklore and stories.