Originally Posted by
UAPremExecflyer
Slightly OT, but there is no such place as "Eire"! It is the Republic of Ireland or various derivations, like "Irish Republic". "Eire" is on the country's stamps. It's like calling Germany "Deutschland". Technically you can walk across the border from Northern Ireland into the Republic and vice versa. And locals do. You can cross on many small rural country roads. Some of these crossings are used for smuggling (of fuel, cigarettes etc) and other nefarious activities. Also walking across the frontier on one of those roads could also mean you make the acquaintance of heavily armed police officers on either side of the border

. These will not be your average "beat" officers but counter-terrorism or undercover/the equivalent of plainclothes SWAT officers (if you want a US reference point). And these officers would have lots of questions for you -- rather more than an immigration officer

.
Don't know where you got that from? There is of course a place called Éire, it is the name (in Irish) of the state occupying 26 of the 32 counties of the Island of Ireland. I suggest you look at Article 4 of the Constitution of Ireland and that sets it out pretty clearly. Under this Article "Ireland" is simply the English translation of "Éire." However, as the term "Ireland" was/is unacceptable to some British polititians you are right in pointing out that "Éire" has often been used in English as a reference to the 26 county state, excluding Northern Ireland.
"Republic of Ireland" is the official
description of the 26 county state recognised under the Republic of Ireland Act of 1949. However this has been used on and off by the UK (and indeed other nations) as a
de facto name of the Irish State in a similar fashion to the use of the word "Éire" in the English language.
By the way, the police in the border counties are much more concerned about Dissident Republican activities than a few US tourists taking day trips across the border.