The contemporary art dealer Per Skarstedt recently fielded his 20th phone call from dealers inquiring about his third-story gallery space on Madison Avenue and 79th Street. The repeated pleas for Mr. Skarstedt’s 1,600-square-foot quarters are symptomatic of the feverish demand for gallery space on the boutique-choked Upper East Side.

“I looked for three entire years for additional space,” Mr. Skarstedt said. He also just leased the former Salander-O’Reilly gallery space around the corner on 79th Street at Madison Avenue. He aims to open a new 8,000-square-foot gallery there called 1018 Art in May, in partnership with the Chelsea dealers Lawrence Luhring and Roland Augustine, who serves as Art Dealers Association of America president. Together, they plan to maintain Mr. Skarstedt’s current gallery for smaller exhibitions.

The Upper East Side is emerging as prime territory for contemporary art galleries, which have long clustered in Chelsea. Now, even second-floor spaces north of 86th Street are being sought by contemporary art dealers.

At the same time, some specialist dealers, such as Erik Thomsen, who sells 18th- and 19th-century Japanese art, are staking out the galleries far east of Madison Avenue, further expanding the boundaries of the neighborhood as an art district.

“With virtually no space left in Chelsea, more dealers are focusing on uptown, and space is even tight there,” one real estate representative, Susan B. Anthony, said. She is working with several dealers searching for space on the Upper East Side. She said prices for the neighborhood average between $75 and $80 a square foot for space on upper floors, which is double the price of comparable space in Chelsea.

“The Upper East Side is preferable to Chelsea,” Charlie Scheips, who curated a show of 20th-century art that opened last month at Deborah Buck’s private gallery on 94th Street off Madison Avenue. “The really top collectors, who fly in, prefer to stay at the Carlyle and confine themselves to this neighborhood. They don’t care to venture south of 14th Street.”

Ms. Buck, an artist in her own right, opened Buck House on Madison Avenue at 91st Street five years ago, and is capitalizing on the growing interest in art north of 86th Street. A year ago, she gutted a former upholsterer’s workshop to open her satellite private gallery on 94th Street, with 2,000 square feet of space.

Now Ms. Buck is expanding that space by 500 square feet. She calls the design of the new space, which features white brick walls and a poured concrete floor, “downtown industrial chic in an uptown fancy neighborhood.”

Six years ago, dealer Jeanne Greenberg Rohatyn, who heads the Greenberg Van Doren Gallery at Fifth Avenue and 56th Street, launched a private gallery, called Salon 94, in her Rafael Viñoly–designed townhouse on 94th Street. “I started Salon 94 as a destination with not only paintings and sculpture exhibitions but also performances and lectures,” Ms. Greenberg said. Last year, as traffic through the gallery increased, she opened the space to the public four days a week.

“Chelsea is wonderful,” Ms. Greenberg said, “but coming uptown is equally fun, to see art in a different kind of setting.” Her current show, “Stasis/Front,” features paintings, sculpture, and Polaroids by the one-named artist Carter, who participated in the Whitney Biennial last year. Ms. Greenberg said that since the show opened last week, eight works have sold, with prices up to $25,000.

With ground floor space highly coveted, second-floor galleries are increasingly popular. One contemporary art dealer, Cheryl McGinnis, opened a second-floor gallery on Madison Avenue and 92nd Street a year ago. “There’s been a steady stream of mothers dropping in … and my openings are filled with people from the neighborhood,” Ms. McGinnis said recently. For her current show, “Translucent, Transparent, Transported” — devoted to three Chinese contemporary artists, Zhang Hongtu, Hu Bing, and Lin Yan — prices range between $1,000 and $10,000. Just around the corner, contemporary art dealer Lesley Heller occupies the third floor of a brownstone. She said she doesn’t find the elevated location to be problematic. “I have traffic through the gallery all the time,” Ms. Heller said.

Contemporary-art dealers on the Upper East Side value the neighborhood’s period architecture, compared with the renovated industrial spaces available in Chelsea. “Here, I’m not dealing out of white box,” contemporary-art dealer Jack Tilton, who less than two years ago took over two floors of an 1895 townhouse on East 76th Street near Fifth Avenue, said. The building had been the site of Franklin and Eleanor Roosevelt’s wedding in 1905, and boasts massive fireplaces and rococo moldings. Mr. Tilton said his openings have been packed with people since he moved from West Chelsea, and — even better — sales have increased 20%.