Altorf, or. Altdorf, capital of the canton of Uri, Switzerland, in a deep, narrow valley on the Reuss, near the S. E. extremity of Lake Lucerne, at the X. E. terminus of the St. Gothard road; pop. in 1870, 2,724. It is neatly built, and has a Capuchin convent and an old tower covered with paintings in honor of William Tell, which is popularly believed to occupy the spot where he shot the apple from his son's head, though recent research has proved it to be of a date anterior to the time in which that hero of the Swiss legends figures.