Taken from Wikipedia

The Arizona Legislature is the state legislature of the U.S. state of Arizona. It is a bicameral legislature that consists of a lower house, the House of Representatives, and an upper house, the Senate. There are 60 Representatives and 30 Senators. The state legislature meets in the Capitol Complex in the state capital, Phoenix.

There are 30 legislative districts in Arizona, each of which is a multimember constituency. Each district elects a Senator and 2 Representatives for a two-year term. The crossing of upper and lower house districts into a single constituency is found in only seven U.S. state legislatures: Arizona, Idaho, Maryland, New Jersey, North Dakota, South Dakota, and Washington. Since Representatives and Senators are elected by exactly the same people, each House of the Arizona Legislature tends to have members with identical political philosophies, which is illustrated by the fact (see below) that the Republican party has two-thirds of the seats in each House. This produces, in effect, a “two-house unicameral” legislature.