Plenty of places
In fact, I can't think of one region I've lived in that didn't overwhelmingly favor one party or the other. In my youth, it was a Rust Belt city with an old-guard Demo machine... then a Republican suburb, then another Democratic city (Philly), then a Repub stronghold in the rural back of nowhere... then more Repub suburbs in MO and TX.
No balance anywhere, and quite often the minority party (whichever one that happened to be) didn't bother to field a candidate.