It runs from the Massachusetts state line northward through the town of Vernon to the town of Brattleboro, ending at an intersection with U.S. Route 5 (US 5).

Vermont Route 142 begins at the state border in Vernon, where it continues southbound as Massachusetts Route 142 in the town of Northfield.

Route 142 spends its entire length hugging the river, never straying far from its west bank.

It runs directly next to the river upon crossing into Brattleboro, proceeding into the heart of the town, where it ends at an intersection with US-5 and Route 119, which begins at the same intersection.

US-5 southbound provides access to I-91 at Exit 1, and US-5 northbound provides access to Vermont Route 9 and Vermont Route 30, which intersect less than 0.5 miles (0.8 km) to the north.