Riksdag Riksdag of the Estates, by tradition thought to have first assembled in Arboga in 1435, and in 1866 following reforms of the 1809 Instrument of Government that body was transformed into a bicameral legislature with an upper chamber () and a lower chamber (). The most recent general election was held on 9 September 2018. The Swedish word "riksdag", in definite form "riksdagen", is a general term for "parliament" or "assembly", but it is typically only used for Sweden's legislature and certain related institutions. In addition to Sweden's parliament, it is also used for the Parliament of Finland and the
Riksdag members of the Riksdag are elected in the general elections held every four years. All Swedish citizens who turn 18 years old no later than on the day of the election are eligible to vote in and stand for elections. A minimum of 4% of the national vote is required for a party to enter the Riksdag, alternatively 12% or more within a constituency. Substitutes for each deputy are elected at the same time as each election, so by-elections are rare. In the event of a snap election, the newly elected members merely serve the remainder of the four-year term.