HORICON, N.Y. — Here in the heart of the Adirondacks, the slender Schroon River, meandering through dense stands of hemlock and white pine, is so narrow that you could easily hurl a polished rock from one bank to the other. But ever since a century-old bridge nearby closed several years ago, crossing the river by car here can take up to 10 minutes more.

Local officials had the federal and state money in place to build a replacement bridge about two miles to the north. There was just one problem: The river is flanked by state forest preserve land. Using only 20 feet on each side would have required amending the State Constitution, with voters from Rochester to Ronkonkoma deciding the project’s fate.

In November, voters statewide will face a more expansive question — whether to amend the State Constitution to allow towns to use small pieces of land in the “forever-wild” preserves in the Adirondacks and Catskills for small, but critical public projects like straightening a dangerous curve in a road or drilling a drinking well.

The proposal, one of three ballot questions in New York, would create a 250-acre land bank for the purpose. Under the plan, which was worked out by local officials, state lawmakers and environmental advocates, the State Department of Environmental Conservation would purchase 250 acres of private land, to be added to the state forest preserve, to offset an equal amount of land that towns and villages could access for modest projects alongside local and county roads.