canton is wooded (), while nearly half is used from farming (). or about 2.4% of the canton is considered unproductive, mostly lakes (notably Lake Hallwil) and streams. With a population density of 450/km2 (1,200/sq mi), the canton has a relatively high amount of land used for human development, with or about 15% of the canton developed for housing or transportation. It contains the hot sulphur springs of Baden and Schinznach-Bad, 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 Königsfelden (with fine painted medieval glass) and the remains of the Roman settlement of Vindonissa (Windisch). Fahr Monastery forms a small exclave of the canton, otherwise surrounded by the canton of Zürich, and since 2008 is part of the Aargau municipality of Würenlos. Political subdivisions Districts Aargau is divided into 11 districts: Aarau with capital Aarau Baden with capital Baden Bremgarten with capital Bremgarten Brugg with capital Brugg Kulm with capital Unterkulm Laufenburg with capital Laufenburg Lenzburg with capital Lenzburg Muri with capital Muri Rheinfelden with capital Rheinfelden Zofingen with capital Zofingen Zurzach with capital Zurzach The most recent change in district boundaries occurred in 2010 when Hottwil transferred from Brugg to Laufenburg, following its merger with other municipalities, all of which were in Laufenburg. Municipalities There are (as of 2014) 213 municipalities in the canton of Aargau. As with most Swiss cantons there has been a trend since the early 2000s for municipalities to merge, though mergers in Aargau have so far been less radical than in other cantons. Coat of arms The blazon of the coat of arms is Per pale, dexter: sable, a fess wavy argent, charged with two cotises wavy azure; sinister: sky blue, three mullets of five argent. The flag and arms of the canton of Aargau date to 1803 and are an original design by Samuel Ringier-Seelmatter; the current official design, specifying the stars as five-pointed, dates to 1930. Demographics Aargau has a population () of . , 21.5% of the population are resident foreign nationals. Over the last 10 years (2000–2010) the population has changed at a rate of 11%. Migration accounted for 8.7%, while births and deaths accounted for 2.8%. Most of the population () speaks German (477,093 or 87.1%) as their first language, Italian is the second