Lake Thingvallavatn, Southwest Iceland, Iceland

Lake Locations:

Iceland - Southwest Iceland -

Also known as:  Lake Thingvalla

Lake Thingvallavatn (Icelandic), also known as Lake Thingvalla (English) is the largest natural lake in Iceland, boasting a surface area of 20,757 acres and a maximum depth of 374 feet. The northern tip of the lake is situated within the first of the country’s four national parks: Thingvellir National Park. With majestic snowcapped mountains as its backdrop, Lake Thingvallavatn is visually stunning. It is mostly spring-fed and lined with trees, shrubs and flowers.

A veritable heaven for geologists, Lake Thingvallavatn’s faults and fissures are subjects of endless fascination. The area is technically a part of two continents: Europe and America. Aside from the Great Rift Valley in East Africa, this is the only place in the world where the effects of the drifting tectonic plates can be observed; they move at least .8 inch annually. Because the two landmasses are constantly drifting apart, the earth here is always sinking. This has resulted in the formation of the huge rift valley that can be observed today.

Because Lake Thingvallavatn and its surroundings have such a rich history, UNESCO added Thingvellir National Park it to its World Heritage List in 2004. The site of the world’s very first parliament back in 930 A.D., this area was also the first to officially adopt Christianity as a religion in 1000 A.D. Today, the Thingvellir National Park offers facilities that include an interpretive learning center with multimedia programs and educational exhibits. The preserve also features camping grounds and toilet facilities.

Maintained by Landsvirkjun Power, Lake Thingvallavatn’s hydroelectric dam is located at the Sog River outflow point; at 11.8 miles in length, the Sog River is the largest glacial river in Iceland. Water flows through a tunnel and into a tank, then to a pair of turbines with 13.5 MW capacities each. This dam supplies electricity to nearby towns including Reykjavik.

Lake Thingvallavatn has a mean depth of 112 feet, and is famous for its salmon population. Brown trout, three spine stickleback and at least four species of char are also present. Fishing on the lake is permitted 24 hours a day from May 1-September 15, by fly, worm and lure baits only.

For lovers of the outdoors, there are plenty of things to do at Lake Thingvallavatn, including swimming, sailing, and ATV tours. Birdwatching for waterfowl is top notch at the lake, and patient wildlife lovers will find opportunities to spot rare northern divers, Gyrfalcons and barrow’s goldeneyes. More commonly found species include mergansers, mallards and tufted ducks. During the winter, snowmobiling is another great pastime. Golf enthusiasts will appreciate South Iceland’s 16 golf courses.

For scuba divers at Lake Thingvallavatn, the Silfra Rift is one of the top dive destinations on the planet. Freezing cold glacial waters create spectacular seascapes and unparalleled visibility of 330+ feet. Don’t expect to see many fish, but do be prepared for some of the most colorful underwater scenery imaginable. The water is so immaculate and fresh that many consider it safe enough to drink. Silfra Lagoon and Silfra Cathedral are the two main dive sites here, along with nearby Geysir and Gullfoss.

Speckled with beautiful volcanic islands, Lake Thingvallavatn is perfect for canoeing and kayaking. Hiking trails abound, winding through deserted forests and abandoned farmsteads as if they were plucked right out of an oil painting. The trail to the Oxarafoss Waterfall is a particularly peaceful and worthwhile route.

Horseback riding is permitted along many of the paths around Lake Thingvallavatn, leading inland to Western Iceland and to isolated regions of Southern Iceland. The Skogarholar equine camp features tent accommodations and stables for horse campers. Horseback riding is not allowed on the same roads as cars.

Many holiday villa rentals and real estate properties are available around Lake Thingvallavatn. Some feature unobstructed lakeside views and hot tubs. Come visit Lake Thingvallavatn for your next vacation, and see for yourself why it is one of Iceland’s hottest holiday destinations.

Things to do at Lake Thingvallavatn

  • Vacation Rentals
  • Fishing
  • Sailing
  • Swimming
  • Canoeing
  • Kayaking
  • Scuba Diving
  • Golf
  • Camping
  • Hiking
  • Snowmobiling
  • Horseback Riding
  • Waterfall
  • Wildlife Viewing
  • Birding
  • National Park

Fish species found at Lake Thingvallavatn

  • Brown Trout
  • Char
  • Salmon
  • Stickleback
  • Trout

Lake Thingvallavatn Photo Gallery

  • OLYMPUS DIGITAL CAMERA

Lake Thingvallavatn Statistics & Helpful Links

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Lake Type: Natural Freshwater Lake, Dammed

Water Level Control: Landsvirkjun Power

Surface Area: 20,757 acres

Normal Elevation (Full Pond): 330 feet

Average Depth: 112 feet

Maximum Depth: 374 feet

Water Volume: 2,310,536 acre-feet

Water Residence Time: 300 days

Drainage Area: 386 sq. miles

Trophic State: Oligotrophic

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Trophic State | LakeLubbers

Trophic State measures the level of algae and nutrients in a lake.

An oligotrophic lake is very clear (blue in color) and does not support much plant or fish life. A hyper-oligotrophic lake is the clearest of all lakes, and is nearly devoid of plants and fish.

A mesotrophic lake is slightly green and supports a moderate degree of plant and fish life. A lake's most desired trophic state is generally this mid-point - the mesotrophic state.

A eutrophic lake is somewhat murky and supports a large amount of plant and fish life. A hypereutrophic lake is clouded with algae, plant life, and fish life. A eutrophic or hyper-eutrophic lake can be difficult to navigate by boat - and is often an unpleasant place to swim.

The use of phosphorus-rich and nitrogen-rich fertilizer on lawns and golf courses surrounding a lake can cause it to become eutrophic or hypereutrophic.


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Catchment or Drainage Area | LakeLubbers

This is the surrounding area that drains into a lake, including land, rivers and their tributaries. This is also known as the lake's "catchment basin".

Small lakes at the highest peaks of mountains have small drainage areas. The world's oceans have the largest drainage areas.


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Lake-Area Population | LakeLubbers

This is the estimated number of people who live in a house with a view of a lake, plus those who self-describe the lake as their home, for example: "I live at Smith Mountain Lake."


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Water Residence Time | LakeLubbers

This is the estimated time that it takes for an amount of water equal to the entire volume of a lake to flow out of - or evaporate from - the lake.

Residence Time can be as short as a few days for fast-flowing small lakes, and can exceed 100 years for slow-flowing large lakes.


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Completion Year | LakeLubbers

This is the year that a reservoir was first filled to the reservoir's normal elevation - or the year that a natural lake was first dammed. A large reservoir can take more than a year to fill after its dam is first closed.

The Grand Anicut in southern India is generally considered the world's oldest dam that still operates. Grand Anicut was constructed in the second century BC. It now impounds an irrigation network that includes roughly one million acres.

You can find many of the the world's newest reservoirs on LakeLubbers. Many of the world's oldest reservoirs appear on the last page of that list.


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Water Volume | LakeLubbers

This is the estimated volume of water that a lake contains -- measured at the lake's normal elevation. By this measure, the world's largest freshwater lake is Siberia's Lake Baikal.

You can find many of the the world's largest lakes (by water volume) on LakeLubbers.

Water Volume can be measured in acre-feet, in cubic miles, or in cubic kilometers. One acre-foot is the amount of water needed to cover one acre (43,560 square feet) to a depth of one foot. One cubic mile equals 3,379,200 acre-feet. One cubic kilometer equals 810,713 acre-feet.

1 acre-foot is equal to 325,851 US gallons. Siberia's Lake Baikal contains about 6,276,367,740,000,000 gallons of freshwater - nearly 1 million gallons for every living person on earth.

The other - and more widely used - measure of a lake's size is the lake's surface acreage. By that measure, the world's largest freshwater lake is North America's Lake Superior.


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Maximum Depth | LakeLubbers

This is the estimated greatest depth of the water in a lake -- measured at the lake's normal elevation. The world's deepest lake is Siberia's Lake Baikal; that lake's maximum depth is estimated at 5,314 feet.

You can find many of the the world's deepest lakes on LakeLubbers. If you select the last page of that list, you will find the (maximum depth of) the shallowest lakes in our database.


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Average Depth | LakeLubbers

This is the estimated average depth of the water in a lake -- measured at the lake's normal elevation. If the water volume and surface area of a lake are known, an estimate of the lake's average depth can be calculated:

Water volume ÷ Surface Area = Average Depth

Example: 1,000,000 acre-feet ÷ 20,000 acres = 50 feet average depth


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Maximum Elevation | LakeLubbers

This is a lake's highest water level, measured by the lake's surface distance above sea level, that can occur during flooding. A lake's highest possible maximum elevation is usually the top of the lake's dam or spillway.

At lakes that include residential development, government regulations usually forbid the construction of homes below a lake's maximum elevation.


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Minimum Elevation | LakeLubbers

This is a lake's lowest water level, measured by the lake's surface distance above sea level, that can be reasonably expected to occur. Low lake levels can occur due to deliberate seasonal draw downs for irrigation or impending snow melt, reduced water inflows, drought and evaporation, residential or commercial water demands, and hydropower generation.

Some lakes' minimum and maximum elevations are virtually the same. Lakes that generate hydropower may vary by several feet - according to power demand. Lakes whose primary purpose is to prevent flooding can seasonally vary by 100 feet or more.

When some lakes reach their minimum elevation, their boat ramps may not be long enough to permit boat access - and boats docked on shallow parts of the lake may end up on dry ground. In those cases, kayakers and shore-based anglers may be among the few happy recreational users of the lake.


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Normal Elevation | LakeLubbers

This is a lake's normal water level, measured by the lake's surface distance above sea level. For a reservoir, this water level is also known as "full pond" or "full pool".

You can find many of the world's highest-elevated lakes on LakeLubbers. Lakes with the lowest elevations (known by LakeLubbers) are shown on the final page of that list.


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Shoreline Length | LakeLubbers

This is the length of the exterior shoreline around a lake - measured at the lake's normal elevation. The shoreline length can be considerably shorter or longer when lake water levels are lower or higher than normal.

A lake with many coves has a much longer shoreline than a lake of similar surface area that is nearly circular in shape.

When known, the shoreline miles that we report in our statistics include only the lake's exterior shoreline, and exclude the shorelines of islands located within a lake's boundaries. In lakes with many islands, those islands' combined shorelines may exceed a lake's exterior shoreline.

You can find many of the world's longest-shoreline lakes on Lakelubbers.


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Surface Area | LakeLubbers

This is the area (acreage, square kilometers, etc.) of the top surface area of a lake - measured at a lake's normal elevation. The surface area can be considerably smaller or larger when lake levels are lower or higher than normal. North America's Lake Superior is the world's largest freshwater lake by this measure.

The other measure of a lake's size is the lake's water volume. By that measure, the world's largest freshwater lake is Lake Baikal in Siberia.

You can find many of the world's largest lakes (acres) on Lakelubbers. There is no widely-accepted minimum surface area that defines a lake. What Lakelubbers describes as a lake, you might call a pond. The smallest lake that Lakelubbers currently includes is Hawaii's 2-acre Lake Waiau.


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Water Level Control | LakeLubbers

This is the organization that controls water releases or outflows from the lake or reservoir. In the USA, this is often the US Army Corps of Engineers, a power company, a municipal water system, an irrigation district, or a paper manufacturing company. In the case of private or gated lakes, a homeowners' association may be the lake's controlling authority.

Many lakes cross borders, including North America's Great Lakes. The control of such lakes and their coveted freshwater may be amicably shared - or hotly disputed.

"Water wars" continue at many lakes as growing populations and crop irrigation needs compete for the freshwater that lakes contain.


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Lake Type | LakeLubbers

There are 3 basic types of lakes that are currently included on LakeLubbers. 2 types may be dammed or not dammed, producing 5 classifications.

- A Reservoir is a man-made freshwater lake that is usually created by damming rivers.

- A Natural Freshwater Lake occurs naturally - often by glacial activity - and has a salinity of less than 30 parts per thousand. It may be dammed to produce electricity or for other reasons.

- A Natural Saltwater Lake occurs naturally and has a salinity of more than 30 parts per thousand (ppt). It may be dammed.

"Brackish" water may be categorized as freshwater or saltwater, depending on its salt content (salinity). Oligohaline water has less than 15 ppt of salt. Mesohaline water has 15-29 ppt. Polyhaline has 30-335 ppt.


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