Lake Union is a freshwater lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 entirely within the Seattle, Washington city limits.

Origins

A glacial

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

 lake, its basin was dug 12,000 years ago by the Vashon glacier, which also created Lake Washington

Lake Washington

Lake Washington is a large freshwater lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest in the state of Washington, after Lake Chelan. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and...

 and Seattle's Green

Green Lake (Seattle)

Green Lake is a freshwater lake in north central Seattle, Washington, USA, within Green Lake Park. The park is surrounded by the Green Lake neighborhood to the north and east, the Wallingford neighborhood to the south, the Phinney Ridge neighborhood to the west, and Woodland Park to the southwest...

, Bitter

Bitter Lake (Seattle)

Bitter Lake is a small lake in northwest Seattle, Washington, USA.The lake covers 19 acres , with a mean depth of 16 feet and a maximum depth of 31 feet . Until 1913, a sawmill was located at its southwest corner. Tannic acid from logs dumped into the lake gave its water a bitter taste and the...

, and Haller Lakes.

Name

Lake Union received its present name from Thomas Mercer

Thomas Mercer

From An Illustrated History of the State of Washington, by Rev. H.K. Hines, D.D., The Lewis Publishing Co., Chicago, IL. 1893 A portrait of Mr. Mercer appears between pages 588 and 589...

, who in 1854 correctly predicted that canal

Canal

Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

s would someday join Lake Washington to Puget Sound

Puget Sound

Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...

 in a "union of waters." The Duwamish called it "Small Lake" (Lushootseed

Lushootseed

Lushootseed is the language or dialect continuum of several SalishNative American groups of modern-day Washington state...

: XáXu7cHoo, literally "small great-amount-of-water," the diminutive form of the word used for Lake Washington).

Geography

Three major streets are named in relation to the lake: Westlake Avenue, which runs along its western shore from Downtown to the Fremont Bridge; Eastlake Avenue, which runs along its eastern shore from Cascade

Cascade, Seattle, Washington

Cascade is a small neighborhood abutting Downtown Seattle, Washington, USA; it constitutes the eastern portion of what has come to be known as South Lake Union...

 to the University District

University District, Seattle, Washington

The University District is a neighborhood in Seattle, Washington, so named because the main campus of the University of Washington is located there. The UW moved in two years after the area was annexed to Seattle, while much of the area was still clear cut forest or stump farmland...

, and Northlake Way, which runs along its northern shore from the University District past Gas Works Park

Gas Works Park

Gas Works Park in Seattle, Washington is a 19.1 acre public park on the site of the former Seattle Gas Light Company gasification plant, located on the north shore of Lake Union at the south end of the Wallingford neighborhood. Gas Works park contains remnants of the sole remaining coal...

 to the edge of Fremont

Fremont, Seattle, Washington

Fremont is a neighborhood in Seattle, Washington. Originally a separate city, it was annexed to Seattle in 1891. Named after Fremont, Nebraska, the hometown of two of its founders, L. H. Griffith and E...

.

Several neighborhoods take their name from the lake: Eastlake

Eastlake, Seattle, Washington

Eastlake is a neighborhood in Seattle, Washington, so named because of its location on the eastern shore of Lake Union. Its main thoroughfare is Eastlake Avenue E., which runs from Howell Street at the northeast corner of Downtown north over the University Bridge to the University District, where...

, Westlake

Westlake, Seattle, Washington

Westlake is a neighborhood in the city of Seattle, in the US state of Washington, named after its location on the western shore of Lake Union. It is a relatively narrow neighborhood, there being only a few blocks between the shoreline and its western limit at Aurora Avenue N., beyond which is Queen...

, Northlake

Northlake, Seattle, Washington

Northlake is a neighborhood in Seattle, Washington, that consists of the southern part of Wallingford, below N 40th Street. It is so named for being on the northern shore of Lake Union. Landmarks are Gas Works Park, with the Wallingford Steps above, and Ivar's Salmon House...

, and South Lake Union

South Lake Union, Seattle, Washington

South Lake Union is a neighborhood in Seattle, Washington, so named because it is at the south tip of Lake Union.The official boundaries of the City of Seattle Urban Center are Denny Way on the south, beyond which is Denny Triangle; Interstate 5 on the east, beyond which is Capitol Hill; Aurora...

.

Industry

Boeing

Boeing

The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...

 began production on Lake Union in 1916. Shipyards, wharves, and sawmills have also dotted the shore.

Recreation

Lake Union's proximity to and scenic views of Seattle make it a popular recreational spot. Seaplane

Seaplane

A seaplane is a fixed-wing aircraft capable of taking off and landing on water. Seaplanes that can also take off and land on airfields are a subclass called amphibian aircraft...

s operated by Kenmore Air

Kenmore Air

Kenmore Air Harbor, Inc., doing business as Kenmore Air, is an American airline with its headquarters on the grounds of Kenmore Air Harbor in Kenmore, Washington, USA, north of Seattle...

 land on and take off from the lake several times a day during the summer. Pleasure boats from Lake Washington

Lake Washington

Lake Washington is a large freshwater lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest in the state of Washington, after Lake Chelan. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and...

 pass through on their way to Puget Sound

Puget Sound

Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...

. The Center for Wooden Boats

Center for Wooden Boats

The Center for Wooden Boats is a museum dedicated to preserving and documenting the maritime history of the Pacific Northwest area of the United States. Unlike most other museums, at CWB the public is invited to touch the exhibits and explore maritime history first hand by rowing, paddling or...

 holds a yearly wooden boat festival.

Parks

Gas Works Park

Gas Works Park

Gas Works Park in Seattle, Washington is a 19.1 acre public park on the site of the former Seattle Gas Light Company gasification plant, located on the north shore of Lake Union at the south end of the Wallingford neighborhood. Gas Works park contains remnants of the sole remaining coal...

 is the largest park on Lake Union and the most popular for Seattleites and visitors. It is the venue for summer concerts and Seattle's major Fourth of July fireworks

Fireworks

Fireworks are a class of explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display. A fireworks event is a display of the effects produced by firework devices...

 show. Other parks ring the lake, clockwise around the compass from Gas Works which is nearly due north: North Passage Point Park

North Passage Point Park

North Passage Point Park is a 0.8 acre park located in the Northlake neighborhood of Seattle, Washington, directly underneath the Ship Canal Bridge on the north side of the Lake Union/Portage Bay shoreline. It was dedicated in 1977. South Passage Point Park is directly across the water on the...

, South Passage Point Park

South Passage Point Park

South Passage Point Park is a 0.9 acre park located in the Eastlake neighborhood of Seattle, Washington, directly underneath the Ship Canal Bridge on the south side of the Lake Union/Portage Bay shoreline. It was dedicated in 1977. North Passage Point Park is directly across the water on the north...

, Fairview Park

Fairview Park (Seattle)

Fairview Park is a park located in Seattle, Washington, on the eastern shoreline of Lake Union along Fairview Avenue E. between E. Hamlin and Allison Streets. It includes a P-Patch and a boat launch.-External links:*...

, Terry Pettus Park

Terry Pettus Park

Terry Pettus Park is a park located in Seattle, Washington, on the eastern shoreline of Lake Union at Fairview Avenue E. and E. Newton Street. It includes shoreline access and a public float....

, and South Lake Union Park

South Lake Union Park

Lake Union Park is a park located at the south end of Lake Union in Seattle, Washington in the South Lake Union neighborhood. The park is owned by the City of Seattle and operated by Seattle Parks and Recreation. The park property was gradually acquired by the City, and the final were...

.

Floating homes

Floating homes line the east and west sides of Lake Union. In Sleepless in Seattle

Sleepless in Seattle

The film was originally to have been scored by John Barry, but when he was given a list of 20 songs he had to put in the film, he quit.#As Time Goes By - Jimmy Durante #A Kiss to Build a Dream on - Louis Armstrong #Stardust - Nat King Cole...

, the character played by Tom Hanks

Tom Hanks

Thomas Jeffrey "Tom" Hanks is an American actor, producer, writer, and director. Hanks worked in television and family-friendly comedies, gaining wide notice in 1988's Big, before achieving success as a dramatic actor in several notable roles, including Andrew Beckett in Philadelphia, the title...

 lived on one of these homes.

Connections to other bodies of water

Part of the Lake Washington Ship Canal

Lake Washington Ship Canal

The Lake Washington Ship Canal, which runs through the City of Seattle, Washington, connects the fresh water body of Lake Washington with the salt water inland sea of Puget Sound. The Ship Canal includes a series of locks, modeled after the Panama Canal, to accommodate the different water levels...

 system, water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 flows into the lake from Lake Washington

Lake Washington

Lake Washington is a large freshwater lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest in the state of Washington, after Lake Chelan. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and...

 through the Montlake Cut

Montlake Cut

The Montlake Cut is the easternmost section of the Lake Washington Ship Canal, which passes through the city of Seattle, linking Lake Washington to Puget Sound. It is approximately long and wide. The center channel is wide and deep....

, and out via the Fremont Cut

Fremont Cut

The Fremont Cut is a part of the Lake Washington Ship Canal—which passes through the U.S. city of Seattle, Washington, linking Lake Washington to Puget Sound—that connects Lake Union to the east with Salmon Bay to the west. It is long and wide. The center channel is wide and deep...

 on its way to Puget Sound

Puget Sound

Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...

. Before construction of the canal

Canal

Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

, Lake Union emptied into Salmon Bay

Salmon Bay

Salmon Bay is that part of the Lake Washington Ship Canal--which passes through the city of Seattle, linking Lake Washington to Puget Sound--that lies west of the Fremont Cut. It is the westernmost section of the canal, and empties into Shilshole Bay, which is part of Puget Sound. Because of the...

 via a creek which followed roughly the same course as the Fremont Cut does today.

Salinity

Because of the connection via the Hiram M. Chittenden Locks

Hiram M. Chittenden Locks

The Hiram M. Chittenden Locks are a complex of locks that sit at the west end of Salmon Bay, part of Seattle's Lake Washington Ship Canal. They are known locally as the Ballard Locks after the neighborhood to their north...

 to the salt water of Puget Sound

Puget Sound

Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...

, there is some saline contamination, which increases in the summer as the inflow rate from Lake Washington

Lake Washington

Lake Washington is a large freshwater lake adjacent to the city of Seattle. It is the largest lake in King County and the second largest in the state of Washington, after Lake Chelan. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and...

 decreases and the locks open more frequently for pleasure craft

Pleasure craft

A pleasure craft is a boat used for personal, family, and sometimes sportsmanlike recreation. Typically such watercraft are motorized and are used for holidays, for example on a river, lake, canal or waterway. Pleasure craft are normally kept at a marina...

.

Competitive Rowing

Lake Union is home to a several rowing centers, including Lake Union Crew, Lake Washington Rowing Club

Lake Washington Rowing Club

Lake Washington Rowing Club is an organization in the greater Seattle area to further the sport of rowing. It trains people ranging in experience from beginners to Olympic-caliber rowers. The club emphasizes mastery of boat-handling skills and values sculling as the principal path to excellence...

 and Pocock Rowing Center

Pocock Rowing Center

Pocock Rowing Center is an amateur rowing club famous for its founder and its ability to produce world-class rowers.-Members on the 2009 US National Team:*Steve Dani Coaching Staff *Bryan Volpenhein Coaching Staff...

, all members of USRowing

USRowing

USRowing is the national governing body for the sport of rowing in the United States. It serves to promote the sport on all levels of competition, including the selection and training of those who represent the US at international level....

. Also rowing out of bodies of water attached to Lake Union are the Seattle Rowing Center and the Conibear Shellhouse, serving the Washington Huskies

Washington Huskies

Washington Huskies is the nickname of the University of Washington's athletic teams. The school is a member of the Pacific-12 Conference. The athletic program is made up of 9 men's sports and 10 women's sports Washington Huskies is the nickname of the University of Washington's athletic teams. The...

.

Seaplane base

Lake Union is home to two seaplane bases: Kenmore Air Harbor Seaplane Base

Kenmore Air Harbor Seaplane Base

Kenmore Air Harbor Seaplane Base is a public use seaplane base located one nautical mile north of the central business district of Seattle, in King County, Washington, United States. It is situated on Lake Union.- Facilities and aircraft :...

 , and Seattle Seaplanes , located one nautical mile (1.85 km) north of the central business district

Central business district

A central business district is the commercial and often geographic heart of a city. In North America this part of a city is commonly referred to as "downtown" or "city center"...

of Seattle.