Theresa May has said it is important Northern Ireland's voice is heard in Brexit negotiations with the European Union.
On a visit to a farm in County Down, the prime minister said: "I want to hear from people in Northern Ireland about what our exit from the EU means to them."
She reaffirmed the government's opposition to a hard border.
"The border is used daily for travel and trade, but it also forms a hugely important part of British and Irish identities, rooted in generations of family history - and this is something that needs to be protected," added the prime minister.
She said the government's commitment to the Good Friday Agreement had been reconfirmed in the agreements made at the European Council last week.
Agriculture and the NI economy
Mrs May was visiting the farm outside Bangor in recognition of the importance of agriculture to the Northern Ireland economy
The PM's trip was designed to mark one year until Brexit.
In a statement ahead of her trip, Mrs May said: "Today, one year until the UK leaves the EU and begins to chart a new course in the world, I am visiting all four nations of the Union to hear from people across our country what Brexit means to them.
"I am determined that as we leave the EU, and in the years ahead, we will strengthen the bonds that unite us, because ours is the world's most successful union.
"The UK contains four proud and historic nations, but together we amount to so much more than the sum of our parts and our union is an enormous force for good."
The DUP's Nigel Dodds called the prime minister's visit a "strong and sure signal" that Northern Ireland would not be left behind when the UK officially leaves the EU next year.
Sinn Féin's deputy leader, Michelle O'Neill, has criticised Mrs May's itinerary because she did not meet the political parties.
Mrs O'Neill said she was not surprised, given that "the majority of assembly members are pro-remain and support staying within the customs union and single market".
"These are the voices that Theresa May continues to ignore as she and the DUP show blatant contempt for the cross-community majority here who voted to remain."
However, a Downing Street spokesperson said this trip is about meeting people and businesses.
They added that the PM met the leaders of both Sinn Féin and the DUP last month.
In her own statement, Mrs May said she was determined that the UK's future will be "bright" after it leaves the EU.
"Having regained control of our laws, our borders and our money, and seized the opportunities provided by Brexit, the UK will thrive as a strong and united country that works for everyone, no matter whether you voted Leave or Remain."