The Wensum Valley is a strip of countryside that follows the River Wensum from its headwaters near West Rudham, Tattersett and South Raynham in West Norfolk, down to central Norwich. This area is about thirty miles long and two miles wide and includes the flood plain, the valley sides and some of the higher plateau land. The unspoilt landscape and wildlife habitats contrast with the more intensively farmed countryside to the north and south of it.

The wider catchment of the river comprises all the land that drains into the Wensum and includes a large part of central Norfolk. There are also the main tributary valleys of the Tat (near Tatterford), the Cat (near Kettlestone), the Whitewater or Wendling Beck (near Dereham), the Blackwater (near Reepham) and the Tud (in Costessey).