A six-year-old public-private project that was aimed at creating affordable housing and an expanded area of conservation land in Chilmark has landed in Dukes County superior court. The project dates to 2007 and involves the town, the Martha’s Vineyard Land Bank and the Howard B. Hillman family.

At issue is a complicated three-way land swap that was four years in the making. In 2007, the Hillman family agreed to donate 10 acres near South Road to the town of Chilmark; six of the 10 acres would be owned by the land bank and the middle of the parcel would be turned into four one-acre affordable housing sites, owned by the town. In exchange, the Hillmans would be granted ownership of the former Hollis Burton Engley house, a town-owned house that is the 10th oldest in Chilmark, and a trail easement would have been moved.

In 2007, Chilmark voters authorized selectmen to execute the deal, and the state legislature created an act authorizing the swap in 2008.

More than five years later, the town has filed a civil case in superior court. The lawsuit against Howard B. Hillman, trustee of the Dora B. Hillman Trust, asks the court to compel the family trust to comply with the deal, arguing that “despite repeated requests by the town, Hillman refuses to perform,” according to the complaint.

In 2009, the complaint said, the trust informed the town and the land bank through counsel that “he does not consider himself bound by the October 1, 2007 writing among the parties and does not intend to appear at any closing scheduled pursuant thereto.”

The complaint goes on to say the town has been ready to live up to the agreement and has spent public money expecting the completion of the agreement. The complaint seeks an order, injunction or judgment compelling Mr. Hillman, as trustee of the trust, to execute all necessary documents and for other relief, including lawyer’s fees.

The Hillman family owns more than 100 acres around the Engley property and the land bank held a trail easement across the middle of that property. The swap called for the land bank to give up the easement in exchange for another trail easement on the border between the Hillman property and a Sheriff’s Meadow property.

In a counterclaim filed in 2010, the Hillmans argued that the land bank’s concession to move the hiking trail from the middle of the lot to the boundary was a “material inducement” to proceed with negotiations. The parties negotiated a conservation restriction for the Engley property, the counterclaim says, and the restriction came back from the state Department of Conservation and Recreation with “substantial edits.”

“More than one year having passed without the transactions contemplated by the agreement having been accomplished, and unacceptable edits to the conservation restriction having been inserted by the commonwealth, Mr. Hillman informed the parties that the agreement was terminated,” the counterclaim states.

In 2007 Chilmark officials and the land bank praised the Hillman family’s generosity, and hailed the deal as a “win, win, win” that was worth four years of negotiation. The swap would have created a broad trail network linking South Road to the Middle Road area and Waskoskim’s Rock Reservation on North Road. The court case was scheduled for trial in the April superior court sitting, but has been pushed back to the first week of August because of court scheduling.