Washington State Route 520
freeway in King County, Washington, US
State Route 520 (SR 520) is a state highway and freeway in the Seattle metropolitan area, part of the U.S. state of Washington. It runs 13 miles (21 km) from Seattle in the west to Redmond in the east. The freeway connects Seattle to the Eastside region of King County via the Evergreen Point Floating Bridge on Lake Washington. SR 520 intersects several state highways, including Interstate 5 (I-5) in Seattle, I-405 in Bellevue, and SR 202 in Redmond.
The original floating bridge was opened in 1963 as a replacement for the cross-lake ferry system that had operated since the late 19th century. In 1964, SR 520 was designated as a freeway connecting I-5 to I-405. An extension to Redmond was proposed later in the decade. In the 1970s and 1980s, sections of the freeway between Bellevue and Redmond were opened to traffic, replacing the temporary designation of SR 920.
Since the 1990s, SR 520 has been expanded with high-occupancy vehicle lanes (HOV lanes) and new interchanges to serve the Overlake area. In 2016, the original Evergreen Point Floating Bridge was replaced by a wider bridge, as part of a multibillion-dollar expansion program that is scheduled to be completed in the 2020s.
The public source identifies “Washington State Route 520” as freeway in King County, Washington, US. This brief keeps that definition visible, then builds a research path around Washington, State and Route.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Washington State Route 520”, the useful work is to connect “freeway in King County, Washington, US” to the records capable of establishing context and consequence.
The strongest evidence will usually combine a dated visual record with documents produced by the authority responsible for the place. The source revision retrieved here is dated Apr 11, 2026. The linked authority identifier is Q836740. VIAF identifies the subject as 315530841. 2 of 2 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1963, 1964 and 2016.
A single description cannot reconcile every naming convention, rebuilding phase or administrative transfer associated with a place. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Treat names, boundaries and functions as historically changeable. Maps, plans, inventories and administrative records can clarify what the place meant at different dates.
- Historic place names
- Jurisdictional context
- Routes into maps and plans
Contemporary maps, plans, listed-building records, estate papers and the responsible local or national archive.
Three-step research path
- Establish the record: confirm the title “Washington State Route 520”, its source revision and the description used here.
- Expand the search: follow Washington State Route 520 primary sources, Washington State Route 520 archive and Washington research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Washington State Route 520”?
- Which authority defined the place, boundary or structure at the relevant date?
- Which earlier names or jurisdictions may reveal additional records?
Search terms from this dossier
This entry incorporates text from “Washington State Route 520” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.