Route 640 is a 35.9-kilometre (22.3 mi) long mostly north–south secondary highway in the southwestern portion of New Brunswick, Canada.

It passes Odell Park and travels southwest to exit 3 on Route 8.

The road then travels across Route 2 at exit 281 as it enters Hanwell.

The route passes The Hanwell Recreational Park.

The route passes Yoho Lake as it enters Yoho, and it then crosses a branch of Jewetts Cove before entering Hurley Corner.