The keen historian said it was a "great privilege" to visit Waitangi. In Wellington he had seen the original Treaty, along with the Declaration of Independence from 1835 and the women's suffrage petition of 1893.
"I see the Waitangi Treaty as one of the great foundation documents ... in which two peoples recognising each other's cultures see immense possibilities in each other and are able to go forward together."
Mr Higgins, a long-time Labour MP until elected President in 2011, said he had had two meetings with Prime Minister Jacinda Ardern but what had really moved him was meeting so many Irish people in each place he visited.
They included Christine Allen, a former Advocate journalist who moved to Whangarei from Ireland five years ago, who said meeting the President at Waitangi made her as proud to be a Northlander as she was to be Irish.
"We have aroha for our home in New Zealand and grá mór [love] for our homeland - both beautiful countries with similar cultures and people."
Inside the meeting house the president "spoke beautifully about the connections between Celtic, Maori and Pakeha cultures, and about stepping into the future together with similar ideals," she said.
Alex Lambert, a 19-year-old from Cork now living in Paihia, said Mr Higgins was "a cool and funny man". Meeting him in Northland was ironic because she'd never even got close to the head of state at home.
After the welcome Mr Higgins, accompanied by his wife Sabina, a government minister, a large group of officials and Irish media, was shown the great waka Ngatokimatawhaorua and given a tour of the new Waitangi Museum. Later the delegation took a ferry to Russell for lunch at the Duke of Marlborough. Their last stop was Kerikeri Mission Station.
Security was low-key with a small team of plain-clothes officers from the Diplomatic Protection Squad and, at the Treaty Grounds, a few police iwi liaison officers.
Treaty Grounds chief executive Greg McManus said it was a "great honour" to welcome a current head of state. He hoped to see more in the future given that Waitangi was a fitting place to start or finish a state visit.
Far North Mayor John Carter said the visit, which was being followed by Irish media, was great promotion for the Far North, especially on a spectacular day like Saturday.
Mr Carter and Labour MP Peeni Henare, a Treaty Grounds trustee, presented Mr and Mrs Higgins with carved pounamu pendants.
The 24-day tour of Australasia included six days in New Zealand. Mr Higgins laid wreaths at the Christchurch Earthquake Memorial and Pukeahu National War Memorial, attended Irish community events, gave a lecture at Auckland University, and made a presentation to NZ Rugby in memory of Dave Gallaher, the Irish-born captain of the 1905-06 Originals, who died at the Battle of Passchendaele in 1917.
In 2014 he was the first Irish president to make a state visit to the United Kingdom.