Oregon Historical County Records Guide Jefferson County History
Jefferson County Courthouse Sprawling reservoir Lake Billy
Chinook in Jefferson County was named for a Chinook Indian boy
who joined up with John C. Fremont's second expedition at The
Dalles in 1843. Chinook accompanied Fremont (and Kit Carson of
later fame) south through present day Central Oregon to
California, including a harrowing journey across the Sierra
Nevada Mountains in the heart of winter. While traveling through
what is now Jefferson County, Fremont commented about the chasm-
like valleys and vertical precipices that made the region
impracticable for wagons and barely useable by horses. In an
illustration of the difficulty of the terrain, the howitzer
cannon brought by the expedition had to be disassembled and
carried separately by hand. (Source: Oregon Geographic Names)
Jefferson County was created on December 12, 1914, out of
territory that was once part of Crook County. The county was
named after Mount Jefferson, the second highest