Union Square (Seattle)

Coordinates: 47°36′36″N 122°19′55″W / 47.610°N 122.332°W / 47.610; -122.332
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Union Square
Union Square (Seattle) is located in Seattle WA Downtown
Union Square (Seattle)
Location within downtown Seattle
General information
TypeCommercial offices
Location600 University Street and
601 Union Street
Seattle, Washington
Coordinates47°36′36″N 122°19′55″W / 47.610°N 122.332°W / 47.610; -122.332
CompletedOne Union Square: 1981
Two Union Square: 1989
OwnerUnion Square LLC
Antenna spireTwo Union Square:
797 ft (243 m)
RoofOne Union Square:
456 ft (139 m)
Two Union Square:
741 ft (226 m)
Technical details
Floor countOne Union Square: 36
Two Union Square: 56
Floor areaTwo Union Square: 1,126,400 sq ft (104,650 m2)
Design and construction
Architect(s)TRA Architects
Structural engineerMagnusson Klemencic Associates
Main contractorHoffman Construction Company
Turner Construction
[1][2][3][4][5][6][7] unionsquareseattle.com

Union Square is a skyscraper complex at Sixth Avenue between Union and University Streets in Downtown Seattle, Washington, adjacent to Freeway Park. It consists of two skyscrapers built in the 1980s and primarily used for office space. The entire complex features a 1,100-stall parking garage, a courtyard, a retail plaza spanning three stories and an underground pedestrian concourse that connects with the Fifth Avenue Theater and Rainier Square.[8] Both structures were awarded LEED certification in 2009 and eventually received LEED Platinum certification 6 years later as a result of reduced annual energy consumption by 40 percent through recent renovations.[9] The entire complex is currently managed by Washington Holdings, a real estate firm also known as Union Square LLC which is based in Seattle.[10]


One Union Square[edit]

One Union Square is an aluminum clad 456-foot (139 m) skyscraper consisting of 36 floors with 2 floors below ground.[11] Construction of this class A office building was completed 43 years ago in 1981. It is the first office building in Seattle to house all life-support systems in one location.[11] The architect of One Union Square was TRA.

Two Union Square[edit]

Construction on Two Union Square began in 1987 and was complete by 1989. When accounting for the tip of the flag pole,[9] the 797-foot (243 m) building is the third-tallest building in the Seattle skyline. The Seattle-based architectural firm NBBJ designed the tower, which was dedicated on July 29, 1989. Two Union Square has 56 floors with 1,126,428 square feet (104,649 m2) of rentable space, and an underground concourse connecting to the Seattle Hilton Hotel,[12] and shopping at Rainier Square. It is the first skyscraper to use 19,000 lbs/in.2 high-strength concrete.[5]


  • AB Berstein
  • Alston, Courtnage & Bassetti LLP
  • Apex Companies, LLC
  • Apple, Inc.[13]
  • AmWins
  • Arboretum Mortgage
  • Avenue 55
  • BDO
  • Bennett, Bigelow & Leedom P.S.
  • BlackRock Financial
  • Bush Strout & Kornfeld
  • Chapter 13 Trustee
  • Colliers International
  • Ederer Investment Company
  • Edge Asset Management
  • First Choice Health
  • Flinn Ferguson
  • Floyd|Snider
  • Frazier Healthcare
  • Gordon, Tilden, Thomas, Cordell
  • GreaterGood Network
  • HDR, Inc.
  • Homestreet Bank
  • Horizon Realty Advisors, LLC
  • Integra Realty Resources
  • Jones Lang LaSalle
  • Kidder Mathews
  • Kosmos Management
  • Lasher Holzapfel Sperry & Ebberson
  • LBA Realty
  • Littler Mendelson, PC
  • Lockton
  • The Lyman Group
  • Marcus & Millichap
  • McNaul, Ebel, Hawrot & Nelgren PLLC
  • Morgan Stanley Wealth Management
  • National Center for APEC
  • Northwestern Mutual Financial Network
  • Pacific Project Management (PPM)
  • Paragon Real Estate Advisors
  • Penrith Home Loans
  • Pillar International Insurance Advisors
  • Porter Foster Rorick LLP
  • Protiviti
  • Robert A. Underhill
  • Robert Half International
  • Sashen Ventures
  • Seattle Chamber Music
  • Stoel Rives LLP
  • Taipei Economic and Cultural Office in Seattle
  • USI Insurance Services Northwest
  • Wedbush Securities
  • Williams Kastner
  • Willis Towers Watson

See also[edit]


  1. ^ "One Union Square". CTBUH Skyscraper Center.
  2. ^ "Two Union Square". CTBUH Skyscraper Center.
  3. ^ "Union Square". Emporis.[dead link]
  4. ^ "One Union Square". SkyscraperPage.
  5. ^ a b "Two Union Square". SkyscraperPage.
  6. ^ One Union Square at Structurae
  7. ^ Two Union Square at Structurae
  8. ^ "One Union Square". Washington Holdings. Retrieved March 6, 2017.
  9. ^ a b "Union Square". Union Square Seattle. Retrieved March 6, 2017.
  10. ^ "Seattle firm pays $85M for Marriott hotel in SLU". Seattle Daily Journal of Commerce. July 11, 2016. Retrieved March 6, 2017.
  11. ^ a b GmbH, Emporis. "One Union Square, Seattle - 119484 - EMPORIS". Archived from the original on September 25, 2015.
  12. ^ Seattle Hilton
  13. ^ Yu, Hui-yong (July 20, 2015). "Apple Said to Lease Office Space in Seattle Tower". Bloomberg News. Retrieved August 21, 2016.

Further reading[edit]

  • Aïtcin, Pierre-Claude (1998). High-performance Concrete (1st ed.). London: E & FN SPON. ISBN 0-419-19270-0.

External links[edit]