Times Square and Museum Mile are popular attractions in New York City, but the uptown neighborhood of Manhattan Valley is the final destination for many weary visitors at the end of the day. They often can be seen hauling heavy backpacks to Hostelling International’s New York residence at 891 Amsterdam Ave. from the no. 1 train station on Broadway.

Architect Richard Morris Hunt built the hostel, said to be the world’s largest, in 1883 as a home for war widows. For the past two years, it has been undergoing a $2.5 million restoration, which is now finally set to finish later this month.

With 672 beds, and nearly 100,000 square feet, the hostel is a city landmark, with the Landmarks Preservation Commission overseeing the renovations, including a new slate roof and a refurbished portico.

“On the one hand, we had a practical problem: a leaky roof,” the general manager at the hostel, Tim Westwig, said. “On the other were the historic preservation concerns. It was quite fun.”

When Hostelling International, one of the biggest hostel networks with nearly 80 hostels across the country, took over the building in 1984, it was burned out, vacant, and in danger of being torn down by the city. Not yet a landmark, the building did not have the same restraints on renovations, so the hostel group replaced the original slate roof with asphalt, which is cheaper. But now, the hostel group had to put back the original slate, which is pricier and harder to install. The renovations also included replacing the finials and the dormers.

“The work in many cases is done by hand; it’s a gentle sort of work,” Mr. Westwig, who comes from a family of Maine roofers, said. “I didn’t really even appreciate it until I went out onto the scaffolding. I sort of wish it were closer to the ground so people could see it better.” Closer to the ground, the portico, which used to be the main entrance to the building, has also been refurbished (the hostel’s current entrance is on the south side of the building). For the portico, the Landmarks Preservation Commission gave Hostelling International a grant of $50,000 to offset the total cost of $125,000.

The commission was “concerned that stoop was completely overlooked, so we suggested they revamp the portico,” a preservationist who is the head of the historic preservation grant program, Tenzing Chadotsang, said.

The commission’s grant program looks to give money to institutions in low- to moderate-income neighborhoods, Mr. Chadotsang said. Manhattan Valley fits this description, but the commission was also interested in the building itself.

“The building’s history had a lot to do with our giving the grant,” Mr. Chadotsang said. “The name is kind of funny, just the whole history of the place: its association with a famous architect, that it was made into a hostel, not a fancy hotel. And it really contributed to the revival of the neighborhood.”

The hostel is the only surviving building in New York designed by Hunt, who is known for the Breakers in Newport, R.I., and the Biltmore in Asheville, N.C. The pedestal of the Statue of Liberty and the Metropolitan Museum of Art’s façade on Fifth Avenue are the only other designs by Hunt left in New York.

The building on Amsterdam Avenue was first established by the Association for the Relief of Respectable Aged Indigent Females. The society, one of New York’s first charities, commissioned the building to house widows of the Civil War and the War of 1812. Any woman older than 60 was able to take residence there for $150 and the forfeiting of all personal property.

An addition built by Charles Rich in 1908 included a chapel complete with Tiffany windows (they are now part of the collection of the Morse Museum in Winter Park, Fla.), according to the district manager of the Columbus/Amsterdam Business Improvement District, Peter Arndtsen.

In the 1970s, the building was abandoned by the charity, which couldn’t pay for its upkeep, and used by squatters and drug addicts. It was literally burned out, set afire during the blackout in 1977. The city took over the building in 1978, and it was slated for demolition.

In 1984, Hostelling International, then known as American Youth Hostels, entered the picture, viewing the building as an opportunity to establish a Manhattan residence. In conjunction with a West Side community organization, the Valley Restoration Local Development Corporation, the hostel group acquired the building for $687,500, with the nearly $15 million renovation cost financed through investors and grants. Hostelling International refinanced the building in 2006, and is using those proceeds to pay for the current renovations.

The hostel, which didn’t open its doors until 1990, sleeps between eight and 12 guests per room, and the cost starts at $34 a night. Thousands of travelers sleep at the hostel every year, which is a great benefit to the Manhattan Valley neighborhood, experts say.

“The hostel brings a huge number of visitors to the neighborhood,” Mr. Arndtsen said. “In the past, businesses haven’t seen it as a real force, but they are beginning to.” In addition to the exterior renovations, the hostel has recently redone the kitchen, creating eight separate cooking stations, and revamped the common rooms. “We brought this building back to life, we really care about it. We want to create a hostel that’s design-oriented and lively, not just a cheap place to sleep,” Mr. Westwig said.