The Senate is the upper house of the bicameral Parliament of Australia, the lower house being the House of Representatives. The composition and powers of the Senate are established in Chapter I of the Constitution of Australia. There are a total of 76 senators: 12 are elected from each of the six Australian states regardless of population and 2 from each of the two autonomous internal Australian territories (the Australian Capital Territory and the Northern Territory). Senators are popularly elected under the single transferable vote system of proportional representation.