Carmel Retreat began as the private estate of Clarence Chapman, a New York financier whose principal interests were in mining and shipbuilding. A ship's bell forged by the Menelly Bell Company of Troy, New York in 1903 still reminds visitors of Mr. Chapman's business interests when they visit the site of his summer home in the Ramapo River Valley of New Jersey. He named the estate "Welawiben", a word created by him to connote good health and fellowship.

Located on several hundred acres in the town of Mahwah (a Native American Delaware Tribal word meaning "happy meeting place"), the main lodge, done in the style of Hudson River Valley country homes, sat on the top of hill between two mountain ridges. The 32 room mansion was winterized for year round occupancy in 1910. One entered the house from either the formal west entrance with its stone cobbled drive and grand granite staircase, or from the east side courtyard. The house featured a stately central foyer with a beautiful chandelier, magnificient grandfather clock and hand carved staircase railings. The foyer led into a large dining room on one side and a sitting room on the other. Two enormous and expandable wooden tables were used for banquets. Both had large fireplaces. Among the more unusual architectural features was a "warming porch" with an enormous fireplace and patio. All of these features remain in place today. Numerous bedrooms provided lodging for family and friends.

Eventually Mr. Chapman added a greenhouse, laundry building and carriage house . All of the buildings make extensive use of the massive boulders found throughout the Valley as structural foundations and exterior walls. For their daughters' weddings, the Chapmans added a formal rose garden in a natural valley behind the house.

The Great Depression of 1929 forced the Chapmans to sell off much of their acreage and eventually the heart of the estate itself, the 72 acre Welawiben. George Brinkerhof, an auto parts dealer from Paterson, New Jersey, purchased the house.

In 1954, Father Brice Riordan, O.Carm., bought Welawiben on behalf of the Carmelites as a retreat center. He had also planned for the building to serve as a communication center with a radio station and transmitting tower. While the dream of a radio station was never realized, Carmel Retreat has hosted thousands of retreats, days of reflection, educational programs, seminars, and meetings. Under Fr. Brice's direction, the game room was converted into a Chapel, the laundry building and carriage became guest houses, and the greenhouse continued to function for many years providing plants and flowers for Carmel Retreat and for churches in the area.

The Carmelites and their friends also made several notable contributions to the facilities. The Knights of Columbus of Hackensack and the Columbiettes of New Jersey donated a seven foot marble statue of Our Lady of Mt. Carmel, and a 12 foot crucifix for the Lower Garden. The images are made of beautiful fianco marble from the quarries of Pietrassanta in Tuscany, Italy. They were carved by Joseph Picirilli whose forefathers had been the builders of the city's fourteenth century cathedral. It is said that the face of the Madonna was modeled on that of actress Loretta Young. In 1965, following Pope Paul VI's plea for peace at the United Nations, a Rosary Garden was built. The garden features stations devoted to each of the Mysteries of the Rosary.

In 1988, Carmel Retreat closed for two years while extensive renovations were undertaken. The entire facility was upgraded. In the Main House a new kitchen, remodeled retreatant's bedrooms each with its own bath, and a large addition which included additional guest rooms and a large conference room were among the highlights of the project. At the same time numerous improvements were made to the Lower and Middle Houses.

In 2003 the three houses were renamed the Priory of St. Therese (the Main House), the Hermitage of St. John of the Cross (the Middle House) and the Lodge of Blessed Titus Brandsma (the Lower House). Throughout the Priory, the dominant pictorial images have become those of floral designs in honor of St. Therese, the Little Flower, and religious pictures from the history of the Carmelites.

A new interior design plan for the Priory is restoring the house to more of its original look. Central to this plan is the restoration of a number of pieces of original furniture, refinishing wooden floors, adding vintage lighting, and carpet reminiscent of the early twentieth century. A new garden area was created adjacent to the chapel with the sculpture of Our Lady of Mount Carmel as the centerpiece. A significant renovation of the Lodge was completed to create a facility for groups needing to economize and wishing to have an independent meeting and living area.