Called The River, the 83,000-square-foot (7710 square metres) structure is a series of five pavilions linked by a curved roof, which descend a gently sloping hillside on a former farm site in New Canaan.
Each space includes a different function: a sanctuary, library, gymnasium, orientation centre, and a commons with a cafe. An existing barn on the property has also been transformed, to create an open-air garden and welcome centre.
The pavilions have glass walls, offering 360-degree views out to the rolling landscape, which has been redesigned by Philadelphia firm OLIN. The spaces are staggered under the serpentine roof so as to direct views out on the land, not on the building itself.
"Our goal with The River is to make the architecture become part of the landscape," said SANAA principal Kazuyo Sejima, whose past projects include the Louvre Lens gallery in France and the Rolex Learning Centre in Switzerland.
"We hope that those who are on the property will have a greater enjoyment of the beautiful environment and changing seasons through the spaces and experience created by the River," she said.
The River is SANAA's first project in the US since being awarded the Pritzker Prize in 2010. The studio previously completed the New Museum in New York and the Glass Pavilion at the Toledo Museum of Art in Ohio.
The building distinctive roofline is made of glue-laminated timbers capped with aluminium panels. The warm wood underside contrasts with the silvery metal top, which is intended to reflect the light and sky.
The sanctuary will be used by Grace Community Church as well as other groups in the region. The public is welcome to use the grounds, which includes a system of natural trails and a pond.
Grace Farms is a new 80-acre (32 hectare) reserve of meadows, woods, wetlands and ponds. It opens tomorrow with a two-day programme of events, including the unveiling of new site-specific artworks by Thomas Demand, Teresita Fernández and Susan Philipsz, and a textile piece by Olafur Eliasson.
New Canaan, a wealthy suburban area about an hour outside New York City, is also home to the Philip Johnson Glass House, and many other lesser-known Modernist houses.
Photography is by Iwan Baan, unless otherwise stated.