Idstein is a small town with around 22000 inhabitants between Limburg and Wiesbaden in the county Rheingau-Taunus in Hessen, Germany.

The city has direct half-hourly train connections to Frankfurt, where many of the people living in Idstein work. You can reach also Frankfurt and other important cities within the Rhein-Main area by one of germanies busiest Autobahns. But Idstein has also its own industrial estate. World-wide well known is Black&Decker which has its German headquarter in Idstein. Other companies for example are producing supplies for the car industry.

The medieval town centre together with the Hexenturm ("witch tower") and the palace of the counts of Nassau-Idstein attracts tourist from around the world. The palace built in the current form in the 17th century is now used as a high school (Pestalozzi Gymnasium").

Famous in Idstein is also the Unionskirche ("unification church"), where in 1817 the Protestant and Lutheran church in Nassau was united. From the outside, the church is a simple Gothic building. But inside the ceiling is covered with oil paintings made by scholars of the famous Dutch school of Rubens.

The city was first mentioned in 1102. Rudolf of Habsburg declared Idstein as a town and allowed markets to took place in Idstein in 1287. Soon after that in 1292, one count of Nassau Adolf of Nassau was elected as German king. He reigned only for 5 years.