It comprises 46 legislators, 22 of whom are elected in a single province-wide multi-member district, while the remaining 24 are elected in eight three-member districts that divide the province's territory, called "electoral circuits" (circuitos electorales).

[1] The Legislature was established in 1958, when the National Territory of Río Negro became a province of Argentina.

In 1972, the military governor, Roberto Requeijo, ordered a series of renovations to better accommodate the legislature in the site of the Teatro Argentino.

The electoral circuits do not correspond to the province's departments, but are rather divided using municipalities as its main criterion.

[3] The electoral circuits were first introduced ahead of the 1958 provincial elections, originally comprising six districts.