The road is an east–west highway located entirely within the eastern part of St. Lawrence County.

The NY 72 designation dates back to 1930; however, the route initially followed an entirely different alignment from Potsdam to Hopkinton and was much longer than it is now, extending as far east as Brighton, Franklin County.

Within Parishville, NY 72, named Main Street, crosses the river and intersects the southern end of County Route 47 (CR 47), a connector leading to U.S. Route 11 (US 11) and NY 11C 10 miles (16 km) to the north.

[4][5] East of the hamlet of Parishville, NY 72 turns to the northeast and proceeds on a linear alignment through the towns of Parishville and Hopkinton toward the hamlet of Hopkinton in the northeast corner of the town of the same name.

NY 56 initially continued northwestward from Nicholville to Massena by way of Lawrenceville, North Lawrence, and Winthrop.