It begins at O'Connor Drive near ramps to the Don Valley Parkway, and ends at John Street. North of Steeles Avenue, the road is officially named York Regional Road 12.
Between Sheppard Avenue and Finch Avenue is a planned community called Don Valley Village, built in the 1960s. Here, Don Mills Road splits into two one-way curved boulevards known as Don Mills Road East and Don Mills Road West. This section is called The Peanut due to its shape on a topographic map. It surrounds schools, community centres, and the Peanut Plaza. The road was originally built as a routing beside the eastern banks of the Don River (now called Broadview Avenue) to the original mills on the Don (now called Todmorden Mills). The north-south route in Don Mills is separated as Don Mills North and Don Mills South. Both of these sides are bordered by York Mills Rd, and are far from each other.