The von Klingen family granted extensive lands around the city to the Knights Hospitaller between 1251 and 1268.

Walther of Klingen sold the city and surroundings to his cousin the Bishop of Constance Eberhard von Waldburg in 1269.

Klingnau became the seat of an outer district that included Koblenz, Siglistorf, Mellstorf, Döttingen and Zurzach.

Every year at midsummer the citizens were allowed to elect their lower and upper town council and a municipal court.

From 1415 until 1798, Klingnau was one of the three external districts of the county of Baden during the reign of the Swiss Confederation.

[3] In the 17th century, some Jewish families occasionally lived in Klingnau, and operated the cattle trade for the town.

The growth of the municipal economy was repeatedly interrupted by disasters like the great fire of 1586 in which 84 houses were destroyed, or the plague of 1611 and 1635.

The typhoid epidemic of 1813–14 killed about 3,000 people in and around the town, especially soldiers of the allies against Napoleon, who were passing through.

Between 1931 and 1935, the Klingnau power plant was built for Aarewerke AG, by damming the river.

The lake (Klingnauer Stausee) has developed into a resting place for migratory birds and became a cantonal sanctuary in 1989.

In 1256 Walter of Klingen granted rights to tithes in the town to the kilchen ze Clingnow.

In 1360 the parish of Klingnau included the city, the Chapel of Koblenz and the churches in Döttingen and Würenlingen.

In this year the Bishop of Constance, Heinrich von Brandis, granted the parish church to the monastery Zurzach.

In the late 16th century, the castle, which was the seat of the Governor from Constance, in such bad condition that the Confederates demanded a renovation from the bishop.

The baroque buildings of the Provost's house, the third such structure in the same place, was built by Johann Caspar Bagnato in 1746–53.

East of the town, on the main road is the only monastery of the Hermits of Saint William in Switzerland.

The first industrial enterprises (raw silk production, weaving, straw plaiting and veneer factories) emerged around 1840.

[4] The municipality is located in the Zurzach district, on the right side of the lower Aare valley between the Klingnauer Stausee lake and theAchenberg.

The blazon of the municipal coat of arms is Gules a Mitre Sable lined Or between two Mullets of the last.

[10] About 60.6% of the total households were owner occupied, or in other words did not pay rent (though they may have a mortgage or a rent-to-own agreement).

[14] The historical population is given in the following table:[3] The former Provost's house of the St. Blasien Abbey at Propsteistrasse 1 is listed as a Swiss heritage site of national significance.

[15] The entire village of Klingnau is designated as part of the Inventory of Swiss Heritage Sites.