Neighboring counties which always vote against each other.....

[Redefeatbush04]

Which bordering counties have voted against each other the longest. I haven't checked out all of the states, but here is what I have found so far.

Texas:       McMullen + Duval     (Since 1968)
Alabama:   Macon + Lee           (Since 1964)
Minnesota:  Mower + Olmsted   (Since 1968)
South Dakota:     Sioux + Grant (Since 1960)
Wisconsin:     Ozaukii + Milwaukii (Since 1968)
Montana:     Deer Lodge + Beaverhead (Since 1940)

[minionofmidas]

There's two in central Wisconsin since at least 1960. I've forgot the names; the Republican one begins in Wau-.

[Blerpiez]

Charles City and Henrico, VA - 1960 at least
Yolo and Suter, CA - 1960 at least

[Nym90]

There's two in central Wisconsin since at least 1960. I've forgot the names; the Republican one begins in Wau-.

Waupaca and Portage.

[Redefeatbush04]

Yolo and Suter, CA - 1960 at least

Yes, they go back to 1956, at times Suter is the only republican county in the area. At other times Yolo is the only democratic county in the area. Look especially at the landslides (64/72)

[Hitchabrut]

Essex (Dem) and Morris (GOP), NJ since 1976