Landau was founded in 1224 by the WittelsbachDuke Ludwig of Kelheim. The town had been a Pflegamt for many years and belonged to the Landshut Rentamt of the Electorate-Principality (Kurfürstentum) of Bavaria. Landau possessed a town court with broad magisterial powers (Landgericht).
Until the Bavarian county reform, or Kreisreform in German, in 1972, Landau was the district seat (Kreisstadt) of its own Landkreis, having the license plate code LAN. In the reform, the former townships of Frammering, Mettenhausen, Reichersdorf and Zeholfing, along with parts of the townships of Kammern and Ganacker, were merged with the town of Landau. The incorporation of the townships of Nieder- and Oberhöcking followed in 1978.
Town parish church of the Virgin Mary; the parish church of the Assumption of Dormition of the Mother of God (feast day: 15 August) was constructed during the tenure of the town priest Fr. Phillip Rappoldsberger von Dominikus Magazin in 1713. It counts as the largest and most beautiful Baroque church structure in the lower Isar Valley. The church interior shines with the marvellous Baroque high altar and eight side altars.
The Boulder Church, or Steinfelskirche; the church "At the Thrice-Great Mother in the Rock" originates from the period after the Thirty Years' War and was constructed under Fr. Phillip Rappoldsberger. It houses many votive panels from the 17th and 18th centuries and is counted among the most important pilgrimage churches of the lower Isar Valley.