Location is still by Superintendent Registrar District – I had hoped they’d change this to county
Problem is Lurgan District includes 3 counties (Armagh, Down & Antrim) and appears under all 3 in the NLI District pdf text. Banbridge spans Down & Armagh and even if go down to Sub-District level per the titles at top of births and deaths (not marriages) can still have occasional townlands in another county falling into them. Birth & Death Sub-District is not transcribed and entered into the database, so can't use to assist in splitting into appropriate counties. You would have to include results for Lurgan in its entirety for all 3 counties if county was the (sole) selection parameter.
Co Tyrone includes townlands in Armagh District, so at the moment select Armagh and get a small part of Tyrone (Caledon Sub-District), but if changed to Tyrone county would have to include 8 Sub-Districts in Armagh. It also contains parts of Donegal & Fermanagh. Similarly the seven registration districts that total Co. Monaghan contain or are part of 5 other counties.
Personally prefer them linking to the reference maps and leaving as is. Happy that Antrim does not include Ballymena, Belfast, Larne, Lisburn etc and that Co. Down consists of parts or the entiity of Belfast, Downpatrick, Newtownards, Belfast, Lisburn, Newry and each is searched individually.
Agree the likes of
https://www.swilson.info/regdistmap.php and
https://www.swilson.info/explorer.php can be useful to assist those abroad and those unfamiliar with the district name their ancestor lived in.
They could add County then have a drop down menu select of the Districts within, as FreeBMD does for England and Wales (it even permits selection of multiple districts by use of the shift key). Currently District selection has to be typed in or fine-tuned after an entire island search.