Highland is the city the Morgendorffers claim to move to Lawndale from in the first episode (Esteemsters). It is never officially explained why they left, but a strange offhand comment by Daria to Helen in Esteemsters may be a clue, or just a clever joke. Helen: ...you dont want it to be Highland all over again? Daria: Not much chance of that happening, unless theres uranium in the drinking water here too.