Snowmobilers contend that trails that travel deep into the woods are a key part of the recreational experience.
Attempts at creating a snowmobile plan for the park have been in the works for nearly a decade. The process has involved give-and-take from regulators, local governments and environmentalists.
The lawsuit had listed the APA, DEC and the state Office of Parks Recreation and Historic Preservation as defendants.
APA spokesman Keith McKeever said this week the agency stands by the siting plan and looks forward to its implementation.
"The snowmobile trail guidance represented a significant milestone for the APA and DEC regarding this long-debated State Land Master Plan issue," he said. " Our position was contrary to the Adirondack Council's, and we are satisfied with the court's decision," McKeever said.
He added that APA officials are looking forward, along with their counterparts at DEC, to implementing the trail guidelines though the DEC's Unit Management process.
"We believe the trail guidance embodies a new way forward to help ensure the sustainability of the Adirondack Park," McKeever added.
Snowmobiling is one of the largest components of Hamilton County's winter economy, and it's a key factor in winter tourism in Essex, Warren, Franklin and Clinton counties.
It remained unclear Tuesday whether the Adirondack Council would appeal the decision.