MAKHTAB KHALED, Iraq—Attalaf al Nour, a farmer who lives in Iraq’s Sunni heartland, long enjoyed a simple life that revolved around livestock, crops and trips to the city to sell his grain.
But since July, when Islamic State militants swept into Iraq, his world has been upended by new geographic and political boundaries that don’t yet appear on any map, but is fracturing Iraq’s fragile cohesion by separating thousands of families from their markets, schools and jobs.
“Iraq is broken like never before, thanks to Daaesh,” said Mr. Nour, using the Arabic acronym for Islamic State. “We are all divided and our lives are now upside down.”
Shuttle buses last week running passengers across the Makhtab Khaled checkpoint in Iraq, controlled on one side by Islamic State militants and Kurds on the other. Andrew W. Nunn for The Wall Street Journal
The jihadists’ push has deepened the nation’s splintering into three distinct regional entities: the northeastern region controlled by Kurds and their peshmerga forces, who are pushing for independence; the Sunni region south and west of it, which the Islamic militants largely control, and Baghdad and southern Iraq, where the largely Shiite-dominated national army still holds sway.
These geographic divides are evident at the Makhtab Khaled checkpoint, an imposing new boundary that is both a front line and an economic passage for communities now on Islamic State side of the battle zone but that rely on Kirkuk, a city of half a million people now controlled by Kurds, for basic needs.
Each day about 15,000 people—mostly Sunni Arabs—cross Makhtab Khaled, one of the few civilian crossings along a 400-mile front line across northeastern Iraq from Islamic State-controlled territory into the Kurdish north.
Despite Islamic State’s reputation for brutality, most of these travelers aren’t fleeing the Sunni militants. Rather, they are making the sometimes perilous journey to Kirkuk and returning home, generally more frightened of losing their homes and land and becoming destitute than running afoul of Islamic State.
One such frequent travelers is Mr. Nour, the farmer, who said the economic disruptions of Islamic State’s control over his Salahuddin province have been profound.
“The shops are emptying in Salahuddin. Storekeepers aren’t restocking. Everyone is afraid of the future,” Mr. Nour said. “Kirkuk now is the closest place where we can find choices.”
But in Kirkuk, the Kurds have stopped all cargo transport through the checkpoint for fear the Islamic militants will use trucks to hide explosive devices, creating hardships for rural families in need of crucial goods, including cooking fuel. The Kurds only allow pedestrians to cross at Makhtab Khaled.
On Saturday, Mr. Nour set off from his farm at daybreak with his wife and their five children for a daylong trek to stock up on supplies at Kirkuk’s bazaars.
The trip to the city used to take them two hours in the family’s old Toyota 7203.TO -3.89% pickup truck. Now, a one-way journey lasts more than five hours as the family navigates multiple Islamic State checkpoints to reach the dusty, fallow valley where Makhtab Khaled has been erected.
Travelers seeking to cross the boundary out of Islamic State territory have a complicated one-mile journey along what was, until recently, a busy two-lane highway and is now an eerie no-man’s-land.
The first half mile journey passes a manned Islamic State military post, where the militants’ forbidding black flag is raised. Along the side of the paved highway are fallow, trash-strewn fields and a two-story Kurdish watch tower located about 100 yards away from the militants’ post.
For the next half mile, travelers walk past elaborate sandbagged Kurdish defensive lines, 6-foot trenches and a makeshift barracks to reach the final security check and lines of energetic street vendors and taxi queues.
For those travelers wealthy enough to pay about $1 per passenger, shuttle buses will carry people across. Hundreds of families, like the Nours, however, walk the route.
The Kurdish division responsible for the checkpoint, the First Kirkuk Brigade, closes the checkpoint on days when the front line heats up. One recent day, it remained closed as Kurdish forces fought a six-hour battle with the militants that resulted in at least 12 dead.
The hostilities have resulted in some surprising accommodations between the two sides.
The Kurdish forces at Makhtab Khaled have brokered an agreement with the Sunni tribes who are the traditional community leaders on Islamic State side of the checkpoint to allow ambulances free passage across the two territories to reach the region’s major hospital, said Captain Nasser al-Jaff, who controls security on the Kurdish side.
Those with less critical needs, however, often have to seek aid by walking through the disputed zone.
Abu Ali, a 55-year-old farmer from Tikrit, needs a steady supply of insulin to control his diabetes. His doctors are all in Kirkuk, but his home now lies deep in Islamic State territory. There is no other place for him to go for his medical needs, however, so once a week he takes two of his sons and starts a daybreak journey to Makhtab Khaled.
On a recent afternoon, after finishing his errands in Kirkuk, he joined the swell of people trying to get home. Abu Ali carried one of his sons while the other wheeled a suitcase packed with ice and insulin, so the medicine would stay chilled during the lengthy journey back to Tikrit.
His last purchase was a carton of cigarettes from one of the dozen of street vendors catering to the heavy foot traffic. “No one can sell cigarettes on our side anymore. Daeesh forbids smoking,” he said.
The Nour family, as they returned across the boundary Saturday, said they were worried more about their livelihood now that winter is approaching than the social restrictions Islamic State is mandating in areas it controls.
Although the journey to Kirkuk is tinged with danger, it does have a measure of fun.
On Saturday’s outing, Mr. Nour had bought his 8-year-old boy a black bike with training wheels. His two preschool daughters had brand new barrettes for their hair. He treated himself to a haircut and beard trim—two acts the Islamic State has frowned upon since taking over his village.
The parents are afraid to work their fields now, afraid it is strewed with unexploded ordinance left from recent fighting. With markets tightening, they aren’t sure what prices they could sell a crop, if they were to plant this fall. They carted back across the border in a wheelbarrow a canister of cooking gas and 20 kilograms of rice.
Despite their hardships, the family isn’t contemplating leaving their home for good. Mr. Nour said, “It’s safer in Kirkuk, but where would we live if we left? Who would feed us? Our lives are rooted on our land.”