The New Hampshire Supreme Court has ruled against a group of abutters trying to stop an apartment project in Portsmouth.

The city Planning Board had granted Iron Horse Properties site plan approval and a wetlands-related conditional use permit in 2021 for a 152-unit development and public park on the shores of the city’s North Mill Pond.

But local residents appealed the decision, leading to a long series of back-and-forth legal challenges that led to the early October ruling.

The state Supreme Court ruled that Iron Horse Properties’ project met the criteria for the wetlands permit and that is was providing an important public benefit by proposing to treat stormwater runoff on the site, add native plants and eliminate a derelict, ex-industrial property that had attracted homeless encampments and represented a “safety hazard.” By only slightly encroaching on the 100-foot wetlands buffer, the development was improving the site by removing existing conditions that damage the environment.