Altdorf, Or Altorf, a town of Bavaria, in the circle of Middle Franconia, 13 m. S. E. of Nuremberg, on the Schwarzach; pop. about 3,000. It contains an old palace, and manufactories of wooden toys and breweries. The principal trade is in hops. It was an imperial city before the 13th century, and again rose to importance in the 17th, through its university, which in 1806 was merged in that of Erlangen. The university buildings have since been occupied by a normal school for Protestant teachers.