Tibbitt to Contwoyto Winter Road is an annual ice road first built in 1982 to service mines and exploration activities in the Northwest Territories and Nunavut in Northern Canada. Between 400 and 600 km (250 and 370 mi) long, the road is said to be the world's longest heavy haul ice road and operates for eight to ten weeks starting in the last week of January. Most of the road (85%–87%) is built over frozen lakes, 495 km (308 mi), with the remaining 73 km (45 mi) built on over 64 land portages between lakes.