Named The River in reference to its ribbon-like roof, the building frames both public facilities and meandering walkways for Grace Farms, a new 80-acre (32 hectare) reserve of meadows, woods, wetlands and ponds.
The slender roof is supported by simple columns. Beneath it, a series of glazed volumes accommodate rooms dedicated to art, education and community, including a library, a gymnasium and youth centre, a living and dining room, and a multi-purpose pavilion.
SANAA has also renovated an old barn to create a reception area, as well as education facilities and spaces for the Grace Community Church.
"The intersection of landscape, architecture, art, faith, justice and community will create a new kind of space for visitors and non-profits to collaborate for good," said Sharon Prince, president of Grace Farms Foundation.
"We invite people to shape their own personal experiences at Grace Farms, take a quiet nature walk and have a cup of tea, join an art and architecture tour, see a performance, take part in a justice initiative or reflect on your faith," she added. "The possibilities are as open as the landscape itself."
The landscape design was a collaboration between SANAA and landscape firm OLIN, and includes community gardens, athletics fields and nature trails.
All trees felled during the construction were used to provide wood for the building's furniture.
Grace Farms opens on 9 October with a two-day programme of events, which will include the unveiling of new site-specific artworks by Thomas Demand, Teresita Fernández and Susan Philipsz, and a textile piece by Olafur Eliasson.
Details of these artworks were announced by Kazuyo Sejima at a lecture at New York's Metropolitan Museum of Art, as part of the "In Our Time" series organised by associate architecture and design curator Beatrice Gallilee.
This isn't the first project in the US by the Japanese duo, who are best known internationally for projects including the Rolex Learning Center in Switzerland and the Louvre Lens gallery in France. The pair previously designed the New Museum of Contemporary Art in New York.