A decision by the U.S. Supreme court closes the book on a decades-long court battle over whether private land off Moshup Trail can be opened up for development.

The state SJC handed a legal victory to the town of Aquinnah and others who have been battling a private developer for years over whether land off Moshup Trail can be opened up for development.

Aquinnah landowners who have been battling for nearly 18 years to develop some 30 acres of land off Moshup Trail won a favorable decision this week from the state Court of Appeals, but the convoluted legal saga continues.

An eight-year legal battle over property rights in Aquinnah resurfaced last week when the Massachusetts Court of Appeals reversed a 2001 state land court decision that had the potential to block the development of more than 100 acres of rare coastal heathland off Moshup Trail.

The complicated case centers on whether a group of private landowners and developers should be granted access to a vast area of landlocked lots between Moshup Trail and State Road.

A longstanding land use battle off Moshup Trail in Aquinnah resurfaced on another front this week, when the town conservation commission took up the application of a landowner who wants to build in and around a wetland.

A Middlesex Superior Court judge last week upheld the validity of a unique townwide planning and zoning district in Aquinnah.

The decision, which was entered on Friday by the Hon. Julian T. Houston, found in favor of the town and the Martha's Vineyard Commission against a developer who is seeking to open access to and subdivide parcels of vacant land off Moshup Trail. The developer, James J. Decoulos, has filed more than 10 different legal challenges against the town, a number of which are still ongoing.

Marking a key win for the town of Aquinnah in its long-running legal battle with James J. Decoulos and Maria Kitris, who want to open up Moshup Trail for development, the Massachusetts Appeals Court ruled yesterday on two separate fronts, finding:

• Mr. Decoulos has not won the right to subdivide two lots he owns off Moshup trail.

• The Aquinnah townwide district of critical planning concern is valid.