{"id":7,"date":"2026-10-09T03:53:17","date_gmt":"2026-10-09T03:53:17","guid":{"rendered":"https:\/\/hwy99.us\/?page_id=7"},"modified":"2026-10-09T03:53:17","modified_gmt":"2026-10-09T03:53:17","slug":"california","status":"publish","type":"page","link":"https:\/\/hwy99.us\/?page_id=7","title":{"rendered":"California"},"content":{"rendered":"\n
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01 \/ EXPLORE THE CORRIDOR<\/p>\n\n

Highway 99 in California<\/h1>\n\n

From the Imperial Valley to the Oregon border: an introduction to the route and the places to research next.<\/p>\n<\/div>\n<\/div>\n\n

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A corridor with several chapters<\/h2>\n\n

US 99 crossed the Imperial Valley, the Los Angeles region, the Central Valley, and Northern California. The Sacramento Valley included separate 99E and 99W branches between Sacramento and Red Bluff.<\/p>\n\n

I-5 replaced portions of the corridor, but it is not a complete substitute for tracing old US 99. Other successors include State Route 99, parts of I-10, and numerous local roads.<\/p>\n\n

Sources: Historic Highway 99 Association: California routing<\/a><\/p>\n<\/div>\n<\/div>\n\n

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Explore by region<\/h2>\n
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SOUTHERN CALIFORNIA<\/p>\n\n

Desert & mountain crossings<\/h3>\n\n

Research focus: the Imperial Valley, Los Angeles, the original Ridge Route, and the Ridge Route Alternate.<\/p>\n\n

Explore this section \u2192<\/a><\/p>\n<\/div>\n<\/div>\n\n

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CENTRAL CALIFORNIA<\/p>\n\n

Valley towns & branches<\/h3>\n\n

Research focus: town-center routes, later bypasses, and the distinct histories of 99E and 99W in the Sacramento Valley.<\/p>\n\n

Explore this section \u2192<\/a><\/p>\n<\/div>\n<\/div>\n\n

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NORTHERN CALIFORNIA<\/p>\n\n

Canyons & the state line<\/h3>\n\n

Research focus: Red Bluff, Redding, the Sacramento River corridor, Yreka, and approaches to Oregon.<\/p>\n\n

Explore this section \u2192<\/a><\/p>\n<\/div>\n<\/div><\/div><\/div>\n<\/div>\n\n

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A useful first case study: the Ridge Route<\/h2>\n\n

The original Ridge Route opened in 1915, before US highway numbering. The Ridge Route Alternate followed in 1933, and later freeway construction changed the mountain crossing again. It is a useful place to examine how one corridor can contain several generations of road.<\/p>\n\n

Sources: Ridge Route Preservation Organization<\/a><\/p>\n\n

How this section will grow<\/h2>\n\n

Future entries will work town by town, separating documented street alignments from approximate corridors. A regional overview will never be treated as proof of an exact route line.<\/p>\n

See the mapping approach<\/a><\/div><\/div><\/div>\n<\/div>\n\n
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Continue researching<\/h2>\n\n

California Highways: Route 99<\/a> \u00b7 SoCalRegion: virtual tour<\/a> \u00b7 All research links<\/a><\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

01 \/ EXPLORE THE CORRIDOR Highway 99 in California From the Imperial Valley to the Oregon border: an introduction to the route and the places to research next. A corridor with several chapters US 99 crossed the Imperial Valley, the Los Angeles region, the Central Valley, and Northern California. The Sacramento Valley included separate 99E […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page-no-title","meta":{"footnotes":""},"class_list":["post-7","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/hwy99.us\/index.php?rest_route=\/wp\/v2\/pages\/7","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hwy99.us\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/hwy99.us\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/hwy99.us\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hwy99.us\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7"}],"version-history":[{"count":0,"href":"https:\/\/hwy99.us\/index.php?rest_route=\/wp\/v2\/pages\/7\/revisions"}],"wp:attachment":[{"href":"https:\/\/hwy99.us\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}