Koblenz (or Coblenz) is a town and municipality in the district of Zurzach in the canton of Aargau in Switzerland.

Koblenz is first mentioned in 10th or 11th Century as Confluentia, for the confluence of the Aare and Rhine rivers.

[3] In the Roman era a goods yard and watchtowers existed along the Rhine at this place.

The remaining late Roman watchtower is listed as a heritage site of national significance.

The Koblenz boatmen had a monopoly over transport of goods from the then important market town of Zurzach downstream along dangerous currents of the Rhine towards Basel.

With the arrival of the railway in the 19th century Koblenz and Zurzach lost this important source of income.

The like-named town Koblenz also lies on a confluence of the Rhine, with the river Mosel in Germany.

[7] The age distribution, as of 2008[update], in Koblenz is; 142 children or 9.0% of the population are between 0 and 9 years old and 218 teenagers or 13.8% are between 10 and 19.

[10] About 43% 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][9] The Koblenz Aar railway bridge (shared with Leuggern), the Koblenz–Waldshut Rhine railway bridge and the Kleiner Laufen, a watchtower remnant of the Roman Rhine border fortifications are listed as Swiss heritage sites of national significance.

[8] From the 2000 census[update], 720 or 44.7% were Roman Catholic, while 446 or 27.7% belonged to the Swiss Reformed Church.

Koblenz station is served by Zurich S-Bahn line S36, which links Bülach and Waldshut, and Aargau S-Bahn line S27, which links Baden and Koblenz, with alternate trains continuing to either Waldshut or Bad Zurzach.

Koblenz Dorf station is situated rather closer to the village centre, but is served by fewer trains.