East of its crossing of Ashmere Lake, Route 143 enters the town of Peru and becomes Main Road.

The highway meets Route 112 (Huntington Road) at Worthington Corners, and the two highways run concurrently northeast to where Route 112 splits north near the head of West Falls Branch.

Route 143 crosses the Dead Branch of the Westfield River and enters the town of Williamsburg at the headwaters of Meekin Brook.

The highway, now named Chesterfield Road, follows the brook to its eastern terminus at Route 9 (Williams Street) immediately after crossing the Western Branch of the Mill River in the town center of Williamsburg.

[2] From Hindsale to Worthington, Route 143 is known as the Lafayette Trail, named after American Revolutionary War hero Gilbert du Motier, Marquis de Lafayette,[3] who spent the night in Worthington in 1825.