The presidential elections of 2004 and 2008 obviously had different partisan results, but they also registered distinctly different partisan numbers - a shift from Republicans to Democrats, nationwide, of about 10%. The only significant Republican percentage increases in the presidential were in Alaska (the biggest by far, at 26%), Arkansas, Louisiana and Tenneesee, plus sliver improvements in Oklahoma and West Virginia. The other 45 states, including those which voted Republican both times (such as Idaho), all moved in the Democratic direction.
The Center for American Progress has put together a map on this, showing in the Northwest that Democrats made the largest presidential-level gains in Idaho (13%), closely followed by Oregon (12%) and Washington (10%).
In Washington state, 18 counties (of 39) registered a Democratic shift of more than 10%. The largest shift was in one of the most Republican counties in the state, Chelan County just east of the Cascades, at 15%.
In Oregon, 24 counties of the 36 shifted 10% or more. The highest shift there was in Washington County, at 16% - seemingly a continuation of a general trend in that county.
In Idaho, 21 counties (of 44) shifted 10% or more. As in the other states, most were just above the 10% mark, but one of them - Teton County - registered the largest shift in the whole region, at 23%, as well as the second highest, Power County at 18%. Those are both small counties, but also of interest were the shifts in the two largest counties in the state - Ada (17%) and Canyon (16%).
None of the 119 counties in the Northwest shifted Republican in that pair of presidentials.