To the west it borders the French département Haut-Rhin; to the south the Swiss cantons Basel-Stadt, Basel-Landschaft and Aargau.

The Rhine river, which forms most of the district's southern and western border, is in a narrow valley until it spreads north of Basel in the much wider Oberrheinebene.

The coat of arms of the Lörrach district can be blazoned as Per fess Argent a Demi Lion facing sinister Gules and in base per pale Or a Bend Gules and Azure a Bend Sinister wavy Argent.

The lion in the top part of the coat of arms represents the Lords of Rötteln, who had their primary castle in Loerrach, Wiesental.

The wavy line in the bottom-right represents the small river Wiese, which flows through the district.