For some students, location is the key; for others, it's size. Academics loom large, but so does cost. And then there's the social scene.

These are just some of the factors that students, school counselors and parents say are considered when high school seniors decide where to attend college, a process now in the endgame in hundreds of thousands of homes across the country. This weekend was the deadline at many colleges for students to declare their intention to register, though it also marked the start of a new period of uncertainty for thousands on waiting lists.

The decision often is the hardest one an 18-year-old has had to make, yet for all of its importance, it can turn on intangibles.

Mara Jacobowitz said she remembers how her son, P.J., agonized about whether to attend Indiana University or the State University of New York at Buffalo, which is a few hundred miles from their Long Island home. One day, she said, he woke up with a feeling that he could meet more new people at Indiana, and so he went.

"Notice that the academics had nothing to do with his decision," she said. P.J. is graduating in two weeks, having loved his four years in Bloomington, his mother said.

Ed Sparks, a science teacher at Silver Valley High School in Yermo, Calif., a Mojave Desert town between Los Angeles and Las Vegas, said the small minority of his students who wind up continuing on to college make their decisions "based on dreams" of places they haven't seen -- usually on the East Coast, far from their homes, he said.

Students have "individual assessment systems" for making decisions, said Jim Conroy, the head of the college counseling department at New Trier High School in Winnetka, Ill., but one thing many have in common is they feel pressure to get admitted to elite colleges.

"The perception is that unless you go to the top tier, your life is forever going to be mired in mediocrity, and that's not true," he said. "There's a wonderful girl who I worked with who is going to Valparaiso University in Indiana. It's a fine place, and I see a great future for her there. But again, other kids say, 'You're going to Valparaiso?' It just doesn't have the snob appeal of other schools. It just infuriates me."

There are some who turn down what is conventionally seen as the gold standard of education and pick the school that best suits them. And then there are such people as Lily Warner and Shani Moore, who were able to choose among elites -- yet they, too, allowed some intangibles to guide them.

Following are the stories of how Warner, who will begin college in the fall, and Moore, who is headed to law school, arrived at their decisions.

From the Desert to the District

Lily Warner, 17, chose to attend Georgetown University because, she said, "I got an idea in my head" about living in the nation's capital.

In making that decision, she turned down a full scholarship at the University of California at Berkeley, one of the nation's best public universities in her home state. She also turned down the University of Chicago, Johns Hopkins University and George Washington University.

Warner is one of Sparks's students at the 500-student Silver Valley High School, where, he said, fewer than 10 students each year out of a graduating class of about 90 choose to go to a four-year college. Silver Valley is in an economically depressed area and has a somewhat transient population, Sparks said, with about half of its students coming from military families at Fort Irwin, an Army training center in the Mojave.

Sometimes living in a house that had no hot water, quirky plumbing and a wood-burning stove, Warner said, she was determined to go to a good college. She put herself in that position by earning a 4.6 grade-point average, taking Advanced Placement courses online (except for Sparks's AP classes) and studying for hours every day after school.

Warner said Sparks was an inspiration, because he "didn't allow for slacking off." But Sparks said a small group of high-achieving students, including Warner, got their greatest support from one another and from Silver Valley graduates who came before them and return from college periodically to spur them on.

Warner said that when she realized she could apply to some of the country's leading schools, she looked for high-quality colleges in places where she wanted to live. That, she said, was the key. Even though she comes from a low-income home, finances did not matter most or she would have gone to Berkeley, she said. (The schools that did not offer a complete scholarship put together competitive packages of grants, work study and loans.)

Nor was she going to let the threat of terrorism in Washington keep her away, she said. "You can't plan your life around stuff like that. This is too big a decision."

Warner turned down Berkeley because she had viewed it as her "safety" California school, and she wanted to be in a city far away. She said she knew the University of Chicago had a stellar academic reputation, but her newfound interest in politics, thanks to Howard Dean's unsuccessful presidential campaign, kept bringing her back to Washington, where she had two choices: George Washington University and Georgetown. A trip to the District in February, as part of a school group, gave her the chance to see both campuses. She fell in love with Georgetown's, and that was that.

"I wanted to go to Washington before I got to see the place," she said. "I was partial to Washington, D.C., just because, I don't know, it was an idea in my head. It was the place I wanted to be."

Saying No to Harvard Law

Shani Moore knows very specifically what she wants -- and what she doesn't want.

Moore, a 23-year-old who was born in the District, was raised by her mother after her father died when she was young. Her mother kept her on an educational track, she said, and she wound up graduating from Princeton University and is weeks away from receiving a master's degree in journalism from Berkeley.

Interested in legal affairs reporting -- and perhaps one day practicing law -- she is going to law school in the fall. For Moore, finances were not a concern because, she said, she received a scholarship from the Jack Kent Cooke Foundation. So other concerns took precedence.

She wanted a school that would provide her with both a theoretical framework of the law and nuts-and-bolts training. And she wanted a law school where she would have opportunities to interact with the faculty, "where they care about you and where you will get attention," she said.

She was accepted by all six schools to which she applied, but her decision came down to two: Harvard University and Stanford University.

She chose Stanford, she said, for several reasons. Its law school was smaller than Harvard's, she said, and officials there seem "dedicated" to making law students happy. "I didn't want to go to a place that would make me miserable," she said.

She also was impressed with Stanford's intellectual property law program, and she loves California. Harvard had a great alumni network and a huge faculty to offer, but in the end, it was too big for her.

"Sure, there isn't any other school in the country that has the name 'Harvard,' " she said. "But there were other things important to me. . . . The hardest thing about turning down Harvard is the 'grandmother clause.' What they call the clause is, 'You don't want to tell your grandmother that you turned down Harvard.' "