The Wetterau is a fertile undulating tract, watered by the Wetter, a tributary of the Nidda River, in the western German region of Hesse, between the hilly province Oberhessen and the north-western Taunus mountains. Wetterau dates back to around the 800's with the counts of Wetterau and the House of Wetterau. Bettina von Arnim writes of Wetterau in her text Diary of a Child in the chapter "Journey to the Wetterau."