Interstate 5 in Oregon
section of Interstate Highway in Oregon, United States
Interstate 5 (I-5) in the U.S. state of Oregon is a major Interstate Highway that traverses the state from north to south. It travels to the west of the Cascade Mountains, connecting Portland to Salem, Eugene, Medford, and other major cities in the Willamette Valley and across the northern Siskiyou Mountains. The highway runs 308 miles (496 km) from the California state line near Ashland to the Washington state line in northern Portland, forming the central part of Interstate 5's route between Mexico and Canada.
I-5 was designated in 1957 and replaced U.S. Route 99 (US 99) for most of its length, itself preceded by the Pacific Highway and various wagon roads. The freeway incorporated early bypasses and expressways built for US 99 in the 1950s, including a new freeway route from Portland to Salem, and additional bypasses were built using federal funds. The last segment of I-5, on the Marquam Bridge in Portland, was opened in October 1966 and the whole highway was dedicated later that month. The freeway remains parallel or concurrent to Oregon Route 99 (OR 99) and its spur routes, running along former segments of US 99 that were bypassed by I-5, from Ashland to Portland.
Under Oregon's named route system, all of I-5 is designated as Pacific Highway No. 1. The Salem–Portland section was named the Baldock Freeway until 2022.
This brief starts where responsible research should: with the source description of “Interstate 5 in Oregon” as section of Interstate Highway in Oregon, United States. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the general reference register because the source frames it as section of Interstate Highway in Oregon, United States. Its deeper value depends on whether names, dates, institutions and citations support that framing.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 24, 2026. The linked authority identifier is Q2442449. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1957, 1966 and 2022.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. 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
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Interstate 5 in Oregon”, its source revision and the description used here.
- Expand the search: follow Interstate 5 in Oregon primary sources, Interstate 5 in Oregon archive and Interstate 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 “Interstate 5 in Oregon”?
- Which cited source is closest to the event, object or claim?
- What terminology or title could unlock a more precise catalogue search?
Search terms from this dossier
This entry incorporates text from “Interstate 5 in Oregon” 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.