Altendorf is a municipality in March District in the canton of Schwyz in Switzerland.

The plant continues in use today, and takes its water supply from the Sihlsee reservoir that lies 5 kilometres (3 mi) to the south-west.

Of the rest of the land, 9.4% is settled (buildings or roads) and the remainder (0.4%) is non-productive (rivers, glaciers or mountains).

[4] The municipality is located on the Obersee section of Lake Zurich.

Most of the population (as of 2000[update]) speaks German (91.1%), with Italian being second most common ( 1.4%) and Albanian being third ( 1.3%).

[6] In the 2007 election the most popular party was the SVP which received 47.1% of the vote.

[4] From the 2000 census[update], 3,108 or 67.0% are Roman Catholic, while 810 or 17.5% belonged to the Swiss Reformed Church.