For decades, the 5,525-mile US-Canada border has been lauded as the most peaceful frontier on the planet.

But recent months have shattered that calm with a terrifying wave of immigration crises, drug smuggling, and diplomatic friction between the long-standing allies.

As the amity between Americans and Canadians evaporates, and a trade war takes hold, the world’s longest frontier has become a ground zero for tensions that look set to get worse.

In recent weeks, US border guards have arrested seven ‘suspicious’ Iranian and Uzbek men near the Canadian frontier, while a Canadian man who had lived with his family in the US for years unexpectedly lost his right to reside there.

This marks a sharp turnaround from last year, when the southern US-Mexico was making the headlines, amid a surge of immigrants, including gangsters and militants, under former President Joe Biden’s watch.

The Trump administration has largely shuttered the southern border, with far fewer migrant encounters and crossings in 2025 than in previous recent years. Now, the northern border is getting attention — and for all the wrong reasons.

Speaking at an event in Detroit in June, US Homeland Security Secretary Kristi Noem, said the US-Canada border was replacing the southern frontier as the soft spot for transnational gangsters.

‘When we seal secure areas where criminals may want to cross, they will find new areas,’ Noem told a conservative gathering. She said Canada was allowing drugs and people smugglers across the frontier.

Donald Trump accuses Canada of flooding his country with fentanyl, while Canadian Prime Minister Mark Carney said Ottawa would have to ‘dramatically reduce’ its reliance on Washington DC in the future.

The border area spanning parts of Maine, Vermont and New York has seen record numbers of illegal crossings in recent months  

The border tensions echo the tough talk displayed by Canadian Prime Minister Mark Carney and US President Donald Trump 

‘The old relationship we had with the US based on deepening integration of our economies and tight security and military cooperation is over,’ Carney told reporters in March.

The US-Canada border stretches from the frigid Arctic down to the southern tip of Alaska, and then from the West Coast across North Atlantic, where it separates Maine from New Brunswick.

There were land disputes between the two countries until the 19th century, but for many decades the world’s longest border has been pone of its most peaceful.

It is frequently described as being ‘undefended,’ even though law enforcement are present on both sides.

Fast-forward to 2025, and the situation changes. The Daily Mail takes a look at the recent events that have jangled nerves on both sides of the US-Canada frontier. 

• A tranquil corner of upstate New York was shaken by fears of terrorism on July 1 seven foreign men — including five Iranians — were caught near Mooers Forks by federal agents trying to sneak across the US-Canada border. All the men had previously been arrested for trying to cross into the US illegally, reportedly sparking concern over Iranian sleeper cells operating in the country.
• Chris Landry, a Canadian man and Green Card holder who resided with his partner and five children in New Hampshire, was denied entry into the US after his annual trip back to Canada. Landry was stopped at the border in Maine with three of his children and barred from re-entry, based on cannabis and motoring offenses from the 2000s. ‘I never expected that I wouldn’t be able to go back home,’ he told WMUR. ‘It was scary. I felt like I was being treated like a criminal.’
• American Pie actress Jasmine Mooney, 35, was another Canadian to get caught up in Trump’s crackdown. She was detained for nearly two weeks in March by US immigration officials after being denied entry into the US while travelling from Mexico to San Diego, California. Her work visa had been revoked back in November. She called the experience a ‘deeply disturbing psychological experiment.’
• Kenia Jackeline Merlos and her four American-born children were detained for more than two weeks at a border patrol facility on the US-Canada border after the family was arrested at Peace Arch State Park in Washington state on June 28. The Department of Homeland Security accused Merlos of ‘attempting to smuggle illegal aliens’ into the country, in another sign of stepped-up efforts to crackdown on people without papers.

Chris Landry (pictured) attempted to return home from his yearly trip to Canada, where he is a citizen, but he was stopped at the border in Maine with three of his children and barred from re-entry

Canadians are fearful of visiting the US after the case of Jasmine Mooney, a Canadian former actress who spent 12 days in US immigration custody over a seemingly minor visa problem 

Canadian RCMP officers check the papers of two people who entered Quebec from the US amid a surge

Canadian’s have been angered by Trump’s tough approach to Canada, which he has called a ’51st state’ of the US  

• Quebec authorities in July said they were looking for a group of migrants who were involved in a vehicle crash on the Canada side of the border, after crossing illegally from New York. The 48-year-old driver of the vehicle was arrested for impaired driving. Six to eight passengers, believed to migrants, fled the scene on foot. Quebec has been deluged by asylum seekers headed north amid Trump’s crackdown, many of them Haitians who recently lost their protected status in the US.
• The US in June extradited an ISIS supporter living in Canada who had been caught planning a mass shooting attack on a Jewish center in New York. Muhammad Shahzeb Khan, 20, tried to travel from Canada to New York City in September 2024, but was caught just before he crossed the US border. Khan, also known as ‘Shahzeb Jadoon,’ was charged with attempting to provide material support and resources to ISIS.
• Canada is battling a surge in asylum seekers crossing its southern border from the US, as waves spooked by Donald Trump’s crackdown on illegal immigration flee north in search of safety. St-Bernard-de-Lacolle, the busiest land port between New York and Quebec received 761 asylum claims in the first six days of July. That’s more than quadruple the amount from the same period in 2024, said Canada Border Services Agency (CBSA).
• A similar problem exists on the other side of the border, along what U.S. Customs and Border Protection (CBP) calls the Swanton Sector, which saw 15,000 apprehensions in the 10 months of fiscal year 2024. That was the largest volume ever recorded by the sector, and more than over the course of the previous 13 years combined. Illegal migrants from 85 different countries attempted to cross the 295-mile stretch across Vermont, New York and New Hampshire, CBP said.

Seven Mexican adults were apprehended in the chilly woods of upstate New York, near the Canadian border, in February  

The US-Canada border is getting busier, with a 400 percent surge in asylum applicants at one crossing

These startling incidents come against a backdrop of tensions between the US and Canada over trade — an economic relationship that Trump says undercuts American farmers, auto-makers and others.

Last week, Trump announced he would impose a new 35 percent duty on Canadian goods starting on 1 August, deepening a trade war that started when he took office in January. Carney said this week that some tariffs look set to be part of any coming trade deal with the US.

Will Amos, a former Liberal member of Canada’s Parliament, recently told The New York Times that the centuries-old relationship was heading into uncertain territory, and that the future does not look good.

‘We can be allies but, at the end of the day, Canada’s going to have to look out for number one — and in a much more aggressive way,’ Amos said. ‘It’s not clear whether that’s going to be in the US’s interests. We will see.’