Surface Area
~88 km²
Iceland's largest body of water by surface area after reservoir expansion.
Þórisvatn - Iceland's Largest Reservoir & Highland Lake
Iceland's largest body of water at approximately 88 km², a highland reservoir surrounded by vast, treeless wilderness in the central interior. Enlarged for hydroelectric power and home to trophy brown trout.
Updated February 1, 2026By the Iceland.org Travel Team
Location
Central Highlands
~88 km² · Elevation ~570 m · F-road access only
Þórisvatn is a vast highland lake in Iceland's remote interior, originally a natural lake that was expanded through damming in the 1970s to serve the Búrfell hydroelectric power station. Sitting at roughly 570 meters above sea level, the lake is surrounded by barren, windswept highlands with views stretching to glaciers on the horizon. The area feels like another planet entirely, with almost no vegetation and a profound sense of solitude that defines the Icelandic interior.
Safety + sourcing
Last updated: 2026-02-01
This guide is for trip planning, not emergency guidance. Conditions in Iceland can change quickly—always check official alerts and road conditions before you drive or hike.
Sources to check
Primary Use
Hydroelectric Power
Feeds the Búrfell power station via the Þjórsá river system.
Access
4x4 Required
Highland F-roads only. Typically open late June to September.
What to Expect
Remote Highland Wilderness
Experience Iceland's interior at its most raw and untouched. The landscape is barren and vast, with no trees, buildings, or signs of habitation.
Trophy Brown Trout Fishing
The lake is renowned among anglers for large brown trout. Permits are required and catches of 5+ kg fish are not uncommon.
Glacial Panoramas
On clear days, views extend to Hofsjökull and Vatnajökull glaciers, framing the lake in a surreal highland setting.
Hydroelectric Heritage
The dam and infrastructure tell the story of Iceland's transformation through renewable energy and its harnessing of glacial rivers.
Birdlife on the Shores
Despite its remote location, the lake attracts various bird species including great northern divers and various wading birds during summer.
Midnight Sun Solitude
In June and July, the midnight sun illuminates this otherworldly landscape around the clock, offering uninterrupted exploration.
Getting There
Þórisvatn is accessible via highland F-roads from the south, typically via the Sprengisandur route (F26) or from the Landmannalaugar area. A sturdy 4x4 vehicle is essential as the roads involve river crossings and rough terrain. The lake is approximately 200 km from Reykjavik as the crow flies, but the drive takes significantly longer due to road conditions. Highland roads are generally open from late June to September depending on weather. There are no fuel stations or services in the highlands, so bring all supplies.
Best Time to Visit
Þórisvatn is only accessible during summer when highland roads are open, typically from late June through September. July and August offer the best conditions with relatively mild weather and the longest window of accessible roads. Early summer brings midnight sun and the start of the fishing season. September can offer early northern lights but roads may close unpredictably due to early snowfall. Always check road.is for current highland road status before departing.
Planning help
Þórisvatn FAQs
Quick answers with safety notes where it matters.