California Highways:
www.cahighways.org

This route was defined in 1967.

The corridor functionally acts as a continuation of Route 16 east of the Plymouth area (Route 16 meets Route 49 near Drytown, and then Route 49 continues NNE to Plymouth, where County Sign Route E16 starts).  The portion north of Mormon Emigrant Trail is part of US 50 Alternate.  This alternate route was commissioned during the winter of 1997/1998 following slide closures on mainline US 50. Modern County Sign Route E16 is comprised of what is now Shenandoah Road, Mount Aukum Road and Sly Park Road.  The portion of County Sign Route E16 on Sly Park Road north of Jenkinson Lake has connections to the Gold Rush era of California.  The corridor is roughly aligned over what was the westernmost segment of the Morman Emigrant Trail over Carson Pass which terminated at the Lake Tahoe Wagon Road via Gold Ridge near Pollock Pines. Carson Pass was explored during the 1844 Fremont Expedition.  The route was suggested by Kit Carson to reach Sutter's Fort west from what is now Carson Valley, Nevada. Carson Pass following the 1844 Fremont Expedition would become well known as a good crossing over the Sierra Nevada.  During 1848 Mormon settlers departing California for Utah would construct a roadway originating from the Sly Park area east to Carson Valley via Carson Pass.  Much of the original routing used by the Mormons from Sly Park to Carson Pass in modern times still bears the name "Morman Emigrant Trail.".
(Source: Gribblenation Blog (Tom Fearer), "County Route E16", May 2025)

In 1891, the Morman Emigrant Trail departed the Lake Tahoe Wagon Road eastbound at Forty Mile House (Pollock Pines).  The corridor followed modern Sly Park Road for a couple miles before dipping through what is now Jenkinson Lake to Sly Park House via Carpenters. At that time, the other segments of highway that now comprise County Sign Route E16 existed: Sly Park Road connected west from Sly Park House to the community of Pleasant Valley, and modern Mount Aukum Road crossed the branches of the Consumes River to the vicinity of Bridgeport at the South Fork. During 1955, the Jenkinson Lake reservoir began to flood, and flooded a portion of Sly Park Road that was part of the Morman Emigrant Trail.  It is unclear if the designation of "E16" is coincidence, as the highway functionally acts as an extension of Route 16 and cuts off the Placerville area.
(Source: Gribblenation Blog (Tom Fearer), "County Route E16", May 2025)

During the winter of 1997/1998 large slides closed US 50 over Echo Summit.  US 50 Alternate was commissioned following Sly Park Road on County Sign Route E16, Mormon Emigrant Trail, Route 88 and Route 89.  Despite being signed as an alternative, County Sign Route E16 is intended to be used only during emergencies on mainline US 50; Caltrans never sought a formal designation of US 50 Alternate from AASHTO nor assumed maintenance of new roadway segments.  Morman Emigrant Trail was repaved and had Postmile paddles affixed with "Route 50A" references to aid the California Highway Patrol.  There is no clear evidence that US 50 Alternate signage still exists on Sly Park Road.  As of 2022, US 50 Alternate signage still exists on Mormon Emigrant Trail.
(Source: Gribblenation Blog (Tom Fearer), "County Route E16", May 2025)

• Gribblenation Blog (Tom Fearer): County Route E16

Total mileage: 33.21 mi.

• ⦅Routing⦆
  • Segment 1
  • Segment 2
  • Segment 3
  • Segment 4
• ⦅History and Signage Information⦆
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• ⦅Status⦆
• ⦅Acronyms and Explanations⦆