The Countship of Isenburg-Limburg was a state of the Holy Roman Empire in the 13th and 14th centuries, based around the city of Limburg an der Lahn in modern Hesse, Germany.

The feudal lords of the Countship of Limburg were the Landgraviate of Hesse, Archbishopric of Mainz, and the Holy Roman Empire, each owning a third.

After negotiations, he was able to return to his castle, but he had to grant the citizenry far-reaching freedoms.

The dynasty of the House of Limburg was active on behalf of the German kings.

The city of Limburg an der Lahn was strategically important due to its location on the main trade route from Cologne to Frankfurt.

This led to frequent conflicts with neighbouring lordships and made the city a target of robber-barons.

Under Gerlach II, the city of Limburg achieved its highest medieval flowering.

With a fire in 1342 and the first wave of the Black Death in 1349, however, began its economic decline.

In 1344 half of the castle, town and lordship was pledged to Baldwin of Luxembourg, Archbishop of Trier.