Nevada has become the first state in the US with a female-majority legislature, where women hold 51% of seats.
On Tuesday, Democrats Rochelle Nguyen and Beatrice Duran were appointed to the assembly, replacing lawmakers who had moved on from their posts.
Of Nevada’s 63 legislative seats, 32 are now filled by women.
The historic moment follows an election season that saw an unprecedented number of women win congressional seats.
Former Secretary of State and presidential candidate Hillary Clinton tweeted about the milestone, saying: “Let’s make it the first of many.”
Before the last month’s mid-term elections, 38% of Nevada’s legislative seats were held by women.
Women won seats during the mid-terms, but secured the majority only with Tuesday’s appointments.
In the assembly, women have a majority with 23 of 42 assembly seats. In the Senate, women hold nine of 21 seats.
Ms Nguyen, a criminal defence lawyer, replaced Chris Brooks, who won a Senate seat in November. Ms Duran, a union grievance specialist, replaced Olivia Diaz who is running for a Las Vegas city council seat.
Both received unanimous appointments.
They will both be a part of a Democratic supermajority in the assembly, with the party holding 29 of 42 seats.
Ms Duran told the Associated Press that the milestone was “a great victory” for women; Ms Nguyen said it was “fantastic”.
Nevada now has the highest percentage of female lawmakers, ever, nationwide, at 47.6%. The state’s Supreme Court is also female-led.
Following the elections, the state will now also have two US women senators, Democrats Jacky Rosen and Catherine Cortez Masto.
And it is sending a new female lawmaker, Susie Lee, to the US House of Representatives.
Many have dubbed 2018 the second Year of the Woman given the number of female candidates running for office and winning seats during the 6 November mid-terms.
But while the number of women in state legislatures has more than quintupled since the 1970s, women account for only around 28% of state lawmakers nationwide, according to the National Conference of State Legislatures.
In 2009, women briefly held the majority in New Hampshire’s state Senate, but no state has ever had an evenly split legislature, let alone a female-majority.
According to the Center for American Women and Politics, this year’s “important breakthroughs” are skewed along party lines, with Democrats having far more female candidates than Republicans.
In January, a record-breaking 126 women will serve on Capitol Hill – meaning women will make up just over 23% of Congress.