A nine-part referendum was held in Switzerland on 14 January 1866.^[1] Only two proposals received a majority of votes in favour, and only one had both a majority of votes and majority of cantons.^[1]

In order to pass, the referendums needed a double majority; a majority of the popular vote and majority of the cantons.^[2] The decision of each canton was based on the vote in that canton.^[2] Full cantons counted as one vote, whilst half cantons counted as half.^[2]