History Washington County, Oregon

current county jail in hillsboro.

the provisional legislature of oregon created county twality district on july 5, 1843. twality 1 of original 4 districts of provisional government of oregon in oregon country along clackamas, champooick (later marion), , yamhill counties. columbia, later known hillsboro, selected county seat in 1850. washington county obtained present boundaries in 1854 creation of columbia county north , multnomah county east.

the construction of canyon road beaverton helped portland consolidate position primary port of oregon, , defeat rival efforts of settlements such oregon city , milwaukie.

in november 2004, county , city of beaverton agreed plan city annex both unincorporated residential neighborhoods high-value areas of land. result cedar hills, garden home, raleigh hills, west slope being incorporated 2010, , communities of aloha, bethany, , cedar mill @ point after that.

those plans have since been put on hold after beaverton attempted forcibly annex nike, inc. s world headquarters, have increased nike s taxes substantially. nike lobbied legislature law prohibit annexation 99 years. since decision, annexation plans have been halted, , washington county started urban planning provide city-level services unincorporated urban areas in county.

on january 1, 2014, 160 acres (65 ha) of multnomah county in bethany area transferred washington county. area had been split off washington county when multnomah county created, , transferred allow development of property.