THE MAP PROJECT · RESEARCH STAGE
Every alignment
has a story.
A planned historical overlay of US Highway 99 in California and Oregon, built one documented segment at a time.
PROJECT STATUS
Route layers are not yet available.
This page explains the project. It does not currently contain an interactive map or claim a complete reconstruction of historic US 99.
What the map will show
01
The original route
The earliest documented US 99 alignment in each area. Older Pacific Highway or Ridge Route predecessors will be identified separately when relevant.
02
The changes
Later reroutings, bypasses, and east/west branches, with date ranges and evidence for each segment.
03
The final US 99
The last documented US 99 alignment in each area before its designation was removed. There is no single replacement date for the whole corridor.
Evidence comes with the line
Each future segment will include its location, route or branch, known dates of use, source references, research notes, and confidence level. An uncertain date range will remain a range; an approximate alignment will be marked as approximate.
Planned controls include layer toggles, a date filter, and clickable segment notes. Historic map scans may also be offered as overlays where reuse rights and image quality allow.
From archive to overlay
Find the evidence. Compare dated highway maps, topographic maps, engineering records, and local histories.
Trace and compare. Match identifiable bridges, street intersections, and other landmarks across map editions.
Review and publish. Check each segment against its sources before adding it to the public map.
A map’s publication date and a road’s opening date are different facts. Both will be recorded when known.
Begin with the map collections
USGS topoView provides access to historical topographic maps. ODOT’s history resources point to Oregon highway map collections.
Historical alignment research does not establish present-day public access or road condition.