#4 of 10 for toughest passes in the U.S.
#4. SISKIYOU SUMMIT
Another brief but dangerous stretch of highway known for some of the steepest grades, winding turns, and inclement weather in our Interstate system is Siskiyou Summit. Located just south of Ashland, Oregon, it's the highest pass on I-5 at 4,310 feet above sea level. Depending on which way you're headed (north or south), the summit gains or loses 2,300 feet in altitude in just six miles on its 6 percent grades. The pass' close proximity to the Pacific Ocean combined with its high elevation and hazardous curves, brings with it brutal amounts of snowfall and freezing rain, which are known to force Oregon D.O.T. officials to shut down the entire highway on occasion during winter.
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