Willisau is a municipality in the district of Willisau in the Lucerne canton of Switzerland. It was formed on 1 January 2006 from the municipalitie…Willisau is a municipality in the district of Willisau in the Lucerne canton of Switzerland. It was formed on 1 January 2006 from the municipalities of Willisau Land and Willisau Stadt. On 1 January 2021 the former municipality of Gettnau merged into Willisau.