The canton of Aargau is one of the least mountainous Swiss cantons, forming part of a great table-land, to the north of the Alps and the east of the Jura, above which rise low hills. The surface of the country is beautifully diversified, undulating tracts and well-wooded hills alternating with fertile valleys watered mainly by the Aar and its tributaries. The valleys alternate with pleasant hills, most of which are full of woods.
It contains the famous hot sulphur springs of Baden and Schinznach, while at Rheinfelden there are very extensive saline springs. Just below Brugg the Reuss and the Limmat join the Aar, while around Brugg are the ruined castle of Habsburg, the old convent of Koenigsfelden (with fine painted medieval glass) and the remains of the Roman settlement of Vindonissa (Windisch).
Argovia was the border region between Alamannia and Burgundy, and was a disputed territory between these duchies. A line of the von Wetterau (Conradines) became the counts of Aargau from 750 on and off till about 1030 when they lost it, and in the meantime had taken the name von Tegerfelden From the end of the Hohenstaufen dynasty up to 1415, it was ruled by the Habsburgs, and many historical old castles can be found there. Examples include Habsburg, Lenzburg, Tegerfelden, Bobikon, Stin and Wildegg. There are also a number of former monasteries, such as in Wettingen and Muri. All of these were founded by the Habsburg family. They were closed by the government in 1841, which in 1846, was one of the causes of Switzerland's civil war, the "Sonderbund War". Aargau is also believed to be the ancestral home of Reformist author George Mangold (1822-1894).
In 1415 the Aargau region was taken from the Habsburgs by the Swiss Confederates. Bern kept the south-west portion (Zofingen, Aarburg, Aarau, Lenzburg, and Brugg). Some districts, named the Freie Ämter or free bailiwicks (Mellingen, Muri, Villmergen, and Bremgarten), with the countship of Baden, were ruled as subject lands by all or certain of the Confederates.
10 March - 18 April 1798 it was under French occupation, thereafter the Bernese portion became the canton of Aargau of the Helvetic Republic, the remainder forming the Canton of Baden. In 1803, the two halves were united under the name of canton of Aargau, which was then admitted a full member of the reconstituted Confederation. The Fricktal, ceded in 1802 by Austria, via Napoleonic France, to the Helvetic Republic, was shortly a separate Swiss canton under a Statthalter ('Lieutenant'), but on 9 March 1803 became incorporated as part of the canton Aargau. The chief magistracy of Aargau changed its style repeatedly:
In the year 2003 the canton Aargau celebrated its 200th birthday.
For centuries, two villages in the Aargau, Endingen and Lengnau, were the only places in Switzerland where Jews were permitted to live. They were not permitted to own houses or to live under the same roof with Christians. For the slow process of Jewish emancipation in Aargau and Switzerland, see link below.
Three of Switzerland's five nuclear power plants are in the canton of Aargau (Beznau I + II and Leibstadt). Additionally, the many rivers supply enough water for numerous hydroelectric power plants throughout the canton. The canton of Aargau is often called "the energy canton".
A significant number of people commute into the financial center of the city of Zürich, which is just across the cantonal border.
Tourism is significant, particularly for the hot springs at Baden and Schinznach Bad, the ancient castles, the landscape, and the many old museums in the canton. Hillwalking is another tourist attraction, but is only of limited significance.