It seems that Irish placenames are a bit of a free-for-all. I found two townlands, an hour's walk apart, both called Knockroe [The Red Hill]. Across the country, a rattly ould mix of names derived from Irish by translation [Dublin = the Black Pool] and by transliteration [any town / village / settlement called Ballyxxxxx]; from the local Anglo landlord [Parsonstown - not only what we now call Birr; Edgeworthstown which is fighting off the alternative name Mostrim; Newtownbarry losing ground to Bunclody]. This can result in some unintentionally funny / unfortunate coinages. A townland just West of Kilkenny City called Sceach na Míol = Hawthorn Crataegus monogyna of the jumping louse Cacopsylla crataegi becomes Lousybush in English to the mortification of the girls who live on the Dunningstown Road. Crab lice Pthirus pubis are very distantly related to Psyllidae: last common ancestor 400mya, so you gals can tell any ignorant slaggers, who bring this up, to piss off.
There is a certain irony in The Land of the Free having a much less free-for-all attitude to naming all the creeks, aroyos, peaks, mesas, runs, buttes and passes of their internal geography. Indeed they fund a Board on Geographic Names as a federal body operating under the United States Secretary of the Interior; they collaborate with the US Geological Survey to run GNIS the Geographic Names Information System.
Q. Hey there's a system? run by the Feds? there must be some serious documentation?
A. True, dat: 85 pages of rules, policies, conventions, lists and appendices.
They are absolutely proscriptive about two pejorative words in place names Jap and the N-word. When civil rights got traction in the 1960s, fig-leaf changes were made: Negrohead, TX; Little Negro Creek, IL. And all the Japs got the -anese suffix. But places like Old Paddy Creek, MO; Kraut Canyon, NM; Wop Draw, WY and Dago Joe Spring, NV are not (yet) verboten. You may bet that the next unacceptable toponym will be anything involving squaw. You can search for your own name or naughty words in the database of 2 million named geographical features.
As well as avoiding offence, BGN wants names to be functional, so that they can be written on a map at a sensible font-size and not look bigger than the State Capital. US Postal Service limits Post Office names to 28 characters. So the petitioners' Rear Admiral Richard E. Bennis Reach, NC was accepted as Bennis Reach. Sometimes BGN just roll over as with East Fork North Fork North Fork American River, CA. I bet the BGN are aching to have a bunch of locals petition to rename that watercourse after a dead American hero . . . preferably a Native North American.
And for reasons now lost in the mists of time, the BGN hates possessive apostrophes. It is Pikes Peak therefore not Pike's. Likewise Butlers Toothpick and DEvils Racepath. Since 1890 only five exceptions have been agreed Martha's Vineyard, MA; Ike's Point, NJ; John E's Pond, RI; Carlos Elmer's Joshua Tree, AZ; Clark's Mountain, OR. Other accents and diacrital marks are accepted, indeed willingly embraced, although not essential to searching on their server: too many monoglot anglophone users to get pedantic about fadas.