Concluding four years of negotiations, the Chilmark selectmen this week announced a three-way land swap which will open up a new conservation corridor between North and South Roads and create four affordable homesites in town.

The land swap involves the town, the Martha’s Vineyard Land Bank and the Hillman family, longtime summer residents who own property in Chilmark. No money will change hands in the deal. Final approval will be needed from Chilmark voters, the town planning board and also the state legislature.

The deal is complicated, but in its simplest form, the Hillmans will donate ten acres near South Road to the town; six of the ten acres will be owned by the land bank and the middle of the parcel will be carved into four one-acre homesites owned by the town. In exchange, the Hillmans will take ownership of the former Hollis Burton Engley house, which is currently owned by the town. A trail easement will also be moved.

The impetus for the swap originates with the old Engley property, bought by the town and the land bank in 2002. The property covers nine acres off Middle Road; the Engley house is the 10th oldest house in Chilmark. The town paid $200,000 and took ownership of the house and 4.8 acres, while the land bank paid $1.8 million for the remaining 3.9 acres. The land bank placed a conservation restriction on all but one acre around the Engley homestead. The property also abuts 36 protected acres of Brookside Farm and another 41 acres owned by the Sheriff’s Meadow Foundation.

The town had planned to turn the Engley house into an affordable homesite, but the plans were never completed and the condition of the house is now badly deteriorated.

The Howard Hillman family owns more than 100 acres abutting the Engley property. The land bank had held a trail easement across the middle of the Hillman property. The swap announced this week calls for the land bank to give up its easement; in exchange another trail easement will be placed along the border between the Hillman and Sheriff’s Meadow property.

In the end a land bank trailhead will be located near South Road, leading to a trail that will link through the scenic Middle Road area and eventually on to Waskosim’s Rock Reservation on North Road. Hikers will be able to walk from Six Paths to Nab’s Corner. From there, the path will make its way along the Sheriff’s Meadow Foundation boundary line and into current land bank-owned property, which includes a scenic wildlife preserve. Hikers can then cross a wooden bridge and walk along Brookside Farm to Middle Road. Once across Middle Road, the trail will pick up at the Tiasquam River Reservation and end at the trail head of Waskosim’s Rock.

The deal will add 5.16 acres to land bank holdings. Land bank executive director James Lengyel said this week that the principal benefit of the land swap for his organization is the added trail network. “It’s great to have North and South link,” he said.

He also praised the Hillman family for its generosity. “The land bank appreciates the family’s great love of land and the trust that they’re putting in the land bank,” he said.

Chilmark selectman Frank Fenner, who worked on negotiations for the town, agreed. “The Hillmans are very conservation-minded people,” he said.

Mr. Fenner said the four affordable homesites will also be a boost for the town. “It is my hope that this will alleviate concerns over affordable housing. When coupled with Middle Line [a town-sponsored affordable housing project that is not yet built], we will have the potential to give out ten lots in the near future,” he said. A ground lease on the four affordable lots will be granted to four qualified Chilmark residents; according to the terms of the deal the Hillman family will initially choose the four eligible applicants from a list of prequalified recipients.

Mr. Fenner said the land swap will go on the warrant for a special town meeting on Oct. 29. Informational meetings will be held with the town housing committee on Oct. 1 and planning board on Oct. 9. A public hearing has been tentatively set for Oct. 25. Because the land swap involves the alteration of boundaries and use of land previously subject to conservation restrictions, it will also require a special act of the state legislature.

Despite all the complicated ins and outs, Mr. Fenner said the end result was worth four years of negotiation.

“To me, this is a win, win, win,” he said.