Heading east from the Town of Amherst the route is a two-lane collector highway with a posted speed limit of 80 km/h. In Oxford town limits the route follows Little River Road, Main Street, Water Street and Birchwood Road. From Oxford it continues heading due east with a posted speed limit of 80 km/h until its terminus at Route 368. It was originally part of Trunk 4 until 1970.
Route 204 has been around unofficially for many decades and for many years was the main road between Truro and Amherst. Before the current alignment of Highway 104 was constructed the route was part of the Trans Canada Highway.