They have conquered Williamsburg, colonized the genteel streets of Carroll Gardens and Park Slope, and are moving eastward to Bushwick. Some have defected from Brooklyn altogether, pioneering north to settle new territories in Jackson Heights and Astoria, Queens. Meanwhile, others are eyeing north and east Harlem.

They may not have the economic might or real estate prowess of developers, but the thousands of college graduates who pour into New York each summer in search of jobs, higher education, or merely a good time have become a driving force in shaping the city’s real estate market for the coming year.

“The rental market moves with the academic calendar,” the president of Benjamin James Realty, Douglas Wagner, said. “When school lets out in May, recent graduates flood the market and it becomes incredibly overheated. “

This demand has a two-pronged effect on the housing market. The influx of recent graduates not only sends rents soaring during the summer months – some areas see increases of more than 10% – but it also contributes to the growth of certain communities, as well as the gentrification of others.

“It used to be artists who were the first to start gentrifying neighborhoods,” the Harlem branch manager of Dwelling Quest, Eric Hamm, said. “But I think now, a lot of students can’t find affordable housing in the Village or trendy parts of Manhattan and are looking elsewhere. Where they settle, the rents tend to go up, the bars and restaurants follow, and soon property values increase as well.”

Many real estate agents believe this summer will be the turning point for many neighborhoods in both the outer boroughs and Manhattan.

“I think we are up for a hot summer,” Mr. Wagner said. “What is different is that so many parts of Brooklyn and Queens have become gentrified. … There is going to be a lot of movement.”

The situation in Williamsburg is vastly different from this time last year, said David Maudrell, president of AptsandLofts.com. “It has gotten a lot of press and become one of the trendiest neighborhoods in the U.S. College graduates can’t afford to live there. They will go where it is cheap.”

Mr. Maudrell – who is expecting a “crazy” summer due to the volume of email and calls from graduating seniors looking to move to New York that his agency has received this spring – said that many of those graduates will end up in Bushwick, a neighborhood just east of Williamsburg where rents run about $1,000-$1,300 for a two-bedroom apartment and $1,600 for a three-bedroom – dirt cheap compared to Manhattan. Bushwick also boasts a number of newly renovated loft buildings, which has helped lure college students and graduates to the neighborhood.

“It is kind of like a dorm culture out there,” Mr. Maudrell said. “There are some buildings that are almost completely occupied by students and recent grads.”

Sarah Bleviss, 21, a graduate of Hampshire College, said she is interested in looking beyond gentrified neighborhoods like Williamsburg.

“I am looking for a presence of young people but would prefer a community that is ethnically and socioeconomically diverse,” Ms. Bleviss said. She is less concerned with space than finding a neighborhood that is inexpensive and safe.

Ms. Bleviss is hunting in Brooklyn, but those looking for safe and inexpensive don’t necessarily have to eliminate Manhattan. According to Mr. Wagner, the Upper East Side is becoming increasingly popular among young professionals seeking affordable rents. There are more rental properties on the Upper East Side than anywhere else in the city, making for plenty of choices and reasonable prices, he said.

“For young people, the Upper East Side offers some good deals. There are plenty of vacancies and it hasn’t got a lot of press. We are just beginning to see some new cafes and bars open up in that neighborhood, as well,” Mr. Wagner said.

Northern and East Harlem are also seeing a renaissance of sorts. Mr. Hamm of Dwelling Quest’s Harlem branch has already received a flurry of housing applications for rentals in that area. “For the applications we represent, 75% are either people still in school or just graduating,” he said. “Unlike artists who are seeking raw loft spaces, students are just looking for affordable housing and Harlem provides that, with an easy commute into Midtown.”

Graduates seeking affordable housing can easily find a two-bedroom apartment for $1,200 or a three-bedroom for $1,400, and many are offered with no broker’s fee, Mr. Hamm said.

According to Mr. Hamm, landlords in areas such as Harlem tend to prefer college graduates to artists. “If you take the standpoint of a landlord, artists don’t typically have the general employment or the steady paycheck that recent graduates have,” Mr. Hamm said. “When students come in, landlords expect that they will have guarantors and they would rather rent to someone with greater financial support.”

Catering to a younger clientele also plays to the landlord’s advantage. Some have even tailored their leases to begin and end with the academic cycle. “What happens in the summer is prices go up and landlords are less willing to negotiate,” Mr. Maudrell said. “We tell our clients that if they want deals, look in the dead of winter.”

But will this market saturation dilute graduates’ big-city dreams? No, the challenge only seems to make them stronger.

“There are some locations that people really want to live and if they have to share it with several other people, they will do it to make it possible,” Gary Malin, chief operating officer of Citi-Habitats, said.

“Moving to New York is one of those lifelong obsessions of mine,” Kevin Taylor, a recent graduate of the University of Texas at Austin, said. “So if I don’t go now, I feel like I will never get out of Texas.”

And where would the city be today without big costly dreams? “The East Village would not be the theme park it is now if it weren’t for college students,” Mr. Wagner said. “First the rental market went crazy and then the property values skyrocketed.”