The Refuge is a relatively flat river valley ranging from 20 to 40 ft (6.1 to 12.2 m) above sea level and is surrounded by steep wooded hillsides up to 1,000 ft (300 m) high. The average annual temperature is approximately 73 °F (23 °C), and annual rainfall usually exceeds 75 in (190 cm). At the southeastern end of the Refuge, water from the Hanalei River is diverted into an east and west supply ditch. It then flows northwest and irrigates approximately 186 acres (75 ha) of taro and 84 acres (34 ha) of wildlife impoundments before returning to the river. The Refuge encompasses a total area of approximately 917 acres (371 ha).
Refuge wetlands are closed to the public to protect the endangered waterbirds and taro crops. Limited access is allowed along a county river road. There are interpretive panels located at the Hanalei Valley overlook, across from the Princeville Shopping Center. A new overlook/visitor center is planned for an area adjacent to the refuge near the existing rudimentary overlook.[3]
Hanalei National Wildlife Refuge includes the Hoʻopulapula Haraguchi Rice Mill, which is on the National Register of Historic Places.[4] A nonprofit association conducts historic and environmental education activities for local school groups and visitors under a Special Use Permit.