TENNA, Iraq — Iraq’s dwindling Christians, driven from their homes by attacks and intimidation, are beginning to abandon the havens they had found in the country’s north, discouraged by unemployment and a creeping fear that the violence they had fled was catching up to them.

Their quiet exodus to Turkey, Jordan, Europe and the United States is the latest chapter of a seemingly inexorable decline that many religious leaders say tolls the twilight of Christianity in a land where city skylines have long been marked by both minarets and church steeples. Recent assessments say that Iraq’s Christian population has now fallen by more than half since the 2003 American invasion, and with the military’s departure, some Christians say they lost a protector of last resort.

Their flight is felt in places like the wind-scoured village of Tenna, which has sheltered dozens of Christian migrants over the past nine years. The families fleeing Baghdad’s death squads and bombings found safety here beneath the hulking mountains, but little else besides poverty, boredom and cold. Villagers estimate that half of the 50 or so Christian homes are now empty, their families abroad.

Walid Shamoon, 42, wants to be the next to leave. He said he left Iraq’s capital in January 2011 after a confrontation with Shiite militia members set off a nightmare of escalating death threats and an attempt on his life. A brother had already been killed in a mortar attack six years earlier, so he said he quit his contract job with the Australian Embassy, giving up a $1,500 monthly salary, and came here.

These days, all he can think about is his application to emigrate to Arizona.

“This is not a life,” he said one recent afternoon, as a blizzard raced down from the mountains. “There is no improvement. There is no work.”

Many of the people now struggling in Iraq’s Kurdish north came in the wake of a suicide attack in Baghdad at Our Lady of Salvation Church in October 2010. It was the single worst assault on Iraq’s Christians since the war began, one that left 50 worshipers and 2 priests dead and that turned the church into a charnel house of scorched pews and shattered stained glass.

Christian families in Baghdad grabbed clothing, cash and a few other provisions and headed north for the Christian communities along the Nineveh plain and Kurdistan’s three provinces. They joined tens of thousands of other Christians from the capital, Mosul and other cities who traced similar arcs after earlier attacks and assassination campaigns.

“They traded everything for security,” said the Rev. Gabriel Tooma, who leads the Monastery of the Virgin Mary in the Christian town of Qosh, which took in dozens of families.

The Christians in northern Iraq make up a tiny fraction of Iraq’s legions of displaced people. In all, there are 1.3 million of them across the country, according to the most recent United Nations estimates. Many live in garbage dumps, shanty towns and squalor far worse than anything facing the Christian families in Kurdistan.

Still, Christians and other minorities were singled out in the years of sectarian cleansing that bifurcated a once-diverse Baghdad into pockets of Sunnis and Shiites. Estimates by the United States and international organizations say that Iraq’s prewar Christian population of 800,000 to 1.4 million now stands at less than 500,000.

“The consequence of this flight may be the end of Christianity in Iraq,” the United States Commission on International Religious Freedom wrote in its most recent annual report, summarizing the concerns of church leaders.

In January, the International Organization for Migration found that 850 of 1,350 displaced Christian families it was tracking in northern Iraq had left in the past year. Many cited fears about security as well as the strains of finding work, housing and schools in an unfamiliar place where they had few connections and spoke only Arabic, and not Kurdish.

“No one has done anything for us,” said Salim Yono Auffee, a member of the Chaldean/Assyrian Popular Council, a Christian group in northern Iraq. “These people are trying to figure out how to build their futures, to find homes, to get married. And they are leaving Iraq.”

Even in the relative safety of Kurdistan, some Christians say they still live in apprehension. A kidnapping of a Christian businessman in Erbil, the Kurdish capital, and a recent outbreak of riots and arson attacks against Christian-owned liquor stores in Dohuk Province — the northernmost in Iraq, along the Turkish border — have deeply unsettled Christian migrants to the area.

Seven years ago, after retrieving his son from kidnappers, Salam Meti Abdul Karim moved his family from Mosul to the small Christian community of Shioz, a half-hour’s drive from the center of Dohuk Province. The years passed quietly, until one night in December, when a pickup truck full of men pulled up at the edge of town and set fire to a liquor warehouse.

“I felt like history was repeating itself,” Mr. Abdul Karim said. “We worry the situation is just going to devolve into violence. I was thinking to just take my family and go up to the mountains.”

The village hired armed guards after the attack, Mr. Abdul Karim said.

No Christians were killed in the riots against Christian store owners. Local officials say they were not specifically targeted because of their religion, but because the mobs who burned their stores — and the conservative clerics who had incited them — viewed the alcohol sales as un-Islamic.

Still, Kurdish officials, who have welcomed Christians to the region, rushed to defuse fears conjured by the clash. Massoud Barzani, the Kurdish president, visited Christians in Zakho, the city where the riots were centered, and a parade of government officials and religious leaders emphasized Kurdistan’s historical tolerance, and its deep ties to Assyrians, Chaldeans and other branches of Christianity.

“They are part of us,” said Fadil Omar, the head of the provincial council in Dohuk.

The Kurdish government has offered land, free fuel and other assistance to Christians as they have arrived from Baghdad, and it has opened its universities to students from Mosul, officials say. And Christians do not lack a political voice. They sit on local and provincial councils throughout the north, and hold seats in Parliament in Kurdistan and Baghdad.

Despite the help, many families say they are straining to stay afloat. Those close to cities have found jobs, but those in villages are largely unemployed, and they subsist on government pensions or relief payments of about $200 per month. They skip meals and share heating fuel. They are often miles from schools that teach in Arabic, and some parents say their children have dropped out.

The mountain village of Dawudiyah is a study in trade-offs, a place whose residents share similar stories of fear and flight from their homes in Baghdad. One man was threatened with death if he did not hand over his daughter to militants. A couple’s son was killed on his way home from work. Another family’s son was gunned down with three friends. They gave little thought to the consequences of leaving. They just had to get out.

“It was unbearable,” said Berkho Odeesho, the village’s mayor. “We found safety in Kurdistan, but things are getting unstable. We don’t know where to go.”

But like others here, Mr. Odeesho has a plan. He has applied for an immigration visa, and he is now busy preparing for his consular interview. Uprooting his family from Iraq may be difficult, he said, but it would be in service of a new future, away from Iraq, in a distant place called Illinois.