Scene on the Duke University campus in North Carolina. (Jim R. Bounds/Bloomberg)

As the last of the college acceptances roll in for high school seniors this month, it’s likely more of those offers than ever before will be coming from campuses far from home. Over the last two decades, the number of students traveling a significant distance to college has increased as places that once felt far away now feel as if they are one town over thanks to modern communications and discount airlines.

The trend has only accelerated in recent years as an abundance of college campuses in the Northeast and Midwest struggle to fill their seats given the demographic trends of their surroundings: the high school graduating class of 2020 from states in those two regions is projected to have 80,000 fewer students than the class of 2013, for example.

“There is a recruitment war,” said Jon Boeckenstedt, associate vice president for enrollment management and marketing at DePaul University in Chicago. “Colleges are spending a lot more money to go a lot farther away to get students.”

In seven states, the number of high school graduates leaving to go out-of-state to college has more than doubled since 2008. Those top exporters include Arizona, Georgia, Mississippi, Nevada, North Carolina, Texas, and the biggest of all, California.

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California is fertile ground for colleges looking to go far afield for students. Beyond the fact that there are too many high school graduates for too few seats in the state’s public university systems, students in the Golden State are willing to travel to college. The high school class of 2015 from California, for instance, traveled a median distance of 253 miles to go to college, according to data collected by Hobsons through its college-planning tool, Naviance. By comparison, nationwide, about half of students who attend four-year colleges do so within 100 miles of their home.

As a result, colleges from all over the country are sending admissions officers to California, and in some cases hiring full-time recruiters to be on the ground there. The Regional Admission Counselors of California, which represents out-of-state college recruiters, has some 130 members, more than double what it had in five years ago.

But even as more colleges expand their search area for prospects, there are several signs that the number of students willing to get on a plane or drive several hours to go to college is not keeping pace, according to a study I recently authored on the future of college admissions.

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For one, the students willing to go away to school tend to have the most choices about where they go. They usually have higher test scores and grades and come from upper-income families. But in the decade ahead the biggest growth in high school graduates will be among low-income and Hispanic students whose parents didn’t go to college and who historically have been unable or unwilling to travel far for college.

Second, the campuses with the most geographically diverse student bodies also tend to be the wealthiest and most elite schools in the country. Prestige is the reason students are willing to travel to attend them. The schools now trying to extend their geographic reach are lower-tier colleges without national brand names. The way they attract students from a few states away is to shower them with financial aid. Colleges are discounting their tuition more than ever before, and if that aid ever disappears, so too will the students from far away who often have higher travel costs than their classmates.  “The composition of the recruitment pool is masking the real problem of discounts,” Boeckenstedt said.

Third, while application totals are up at most colleges, including from faraway students, it’s difficult for many colleges to determine the interest of students in actually enrolling. With the exception of elite colleges, the percentage of accepted students who eventually enroll (known as yield rate) has been steadily declining in recent years—from an average of 49 percent in 2002 to 36 percent in 2015. At many schools it’s below 20 percent.

The reason? Students are applying to more colleges than in the past. The proportion of college freshmen who applied to seven or more colleges reached 36 percent in 2015, up from 17 percent a decade ago, and from just 9 percent in 1990. The schools that have benefited the most from this uptick in applications are campuses that really don’t need them. The most selective institutions—those that accept fewer than half of applicants and only represent 20 percent of colleges in the U.S.—accounted for one third of all college applications in 2014.

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High-school counselors told me during the research for my study that not all students are ready at 18 to go away to college, and all of them had stories of former students who had transferred to a school closer to home after their first year because they were homesick or they found it too expensive to be traveling back-and-forth.

The concept of going away to college is a relatively recent phenomenon in American higher education. Until the 1970s and 1980s, most students stayed close to home. As the cost of college skyrockets ever upward and fewer students are willing to travel, there’s a very good chance that higher education might be returning to its local roots.