St. Peter's Basilica

The three-aisled hall church was built from 1619 to 1628 by the court architect Hans Alberthal on the foundations of predecessor churches from the 13th and 15th centuries. The church has cathedral-like dimensions; it is 54.8 meters long, 22.3 meters high, and 22 meters wide. After damage in the Thirty Years' War during the occupation of Dillingen by the Swedes, the church was renovated in 1643. In 1669, the Gothic tower, which still originated from the predecessor church, was raised to 49 meters by David Motzardt, Wolfgang Amadeus Mozart's great-great-grandfather. In 1733, the Erasmus Chapel was added on the north side, and in 1733 and 1734, the stucco work and painting were completed in their current form.

The monastery church of the Franciscan Sisters adjoins the southeast corner of the basilica, and a Lourdes grotto is located at the southwest corner.

In 1978, the organ building company Hubert Sandtner (Dillingen) built the basilica's organ with 47 registers, reusing some registers from the predecessor organ by G. F. Steinmeyer (Oettingen) from 1889. In 2006, the disposition was changed and expanded to 53 registers.

In the bell tower of St. Peter's Basilica hangs a valuable set of three bells from 1724. They were cast on behalf of Count Palatine Alexander Sigismund of Palatinate-Bavaria, Bishop of Augsburg. In 1981, two modern bells were added. The church also possesses a small funeral bell cast in 1716.