Reiden is a municipality in the district of Willisau in the canton of Lucerne in Switzerland. On January 1, 2006 the former municipalities of Langnau bei Reiden and Richenthal were united in the new municipality of Reiden.

Reitnau is a municipality in the district of Zofingen in the canton of Aargau in Switzerland. On 1 January 2019 the former municipality of Attelwil merged into the municipality of Reitnau.