US President Joe Biden will visit here for five days, accompanied by Secretary of State Antony Blinken

He will be accompanied by US Secretary of State, Antony Blinken, making the visit even more high-powered.

It remains possible that First Lady Jill Biden will accompany her husband, and if so she will have some separate engagements.

But officials admit the entire programme could be thrown off course, or cancelled, if President Jimmy Carter dies.

The latter, a fellow Democrat, served as President from 1976 to 1980, when supplanted by Ronald Reagan of the Republican party.

President Carter has been receiving palliative care at home in his native Georgia and is in his final days. There is a tradition of all surviving US Presidents attending the leave-taking of one of their predecessors.

All being well, President Biden will first fly into Northern Ireland and will go to Hillsborough Castle, home of the Anglo-Irish Secretariat.

The next day he journeys to Dublin – but it is unclear whether he will fly or take a motorcade.

Opting for a convoy of vehicles would allow him to make a stop in Co Louth, most likely at Carlingford. He has family roots in the wee county through the Finnegan clan.

The four days in the Republic will involve a public address, whereby citizens can see the President in the flesh.

This could still happen at College Green, scene of Barack Obama’s famous “Is féidir linn” speech from a stage opposite Trinity College.

Alternatively, the speech could be switched to the West of Ireland, where the President will also travel. He has connections in Ballina, Co. Mayo, through the Blewitt family. Officials say the size of expected crowds do not come into it, even though Taoiseach Leo Varadkar promised large crowds when meeting President Biden in the Oval Office for St Patrick’s Day.

President Biden is also scheduled to pay a courtesy visit to President Michael D. Higgins in Áras an Uachtaráin.

The Phoenix Park will be a centre of operations, because the Taoiseach will host a reception for the President at Farmleigh, under a draft schedule for what will be an official visit, not a State visit.

“Having it as an official visit will cut down a lot on the pomp and ceremony,” Independent.ie has been told.

An entourage of up to 800 American officials and journalists are expected to travel for the visit – which could play a role in any planned announcement of the President’s seeking a second term, which many expect.

A press centre will be established at Dublin Castle for the duration, with a regional centre operating in the West for the latter stages of the visit.

It is still unclear whether Air Force One, the iconic Presidential plane, will fly out of Shannon or Dublin on Saturday’s conclusion of the visit. It is expected that the official helicopter, Marine One, will also be deployed to Ireland for the duration.

Events will have pooled coverage, involving Irish and American media teams. Precise events have yet to be pinned down, however, and a round of golf with former Taoiseach Enda Kenny remains unconfirmed, although the two old political and personal friends will still meet.

Key Irish officials are still expecting the White House to make final calls on many of the details, with a wide range of venues and possible events explored.