Most US state legislatures mimic the setup used by the United States Congress. They're "bicameral," meaning they have two houses. Typically, one house includes representatives assigned according to population, while the other assigns representatives by district.
Nebraska is the notable exception. Nebraska has one house, making it "unicameral." Its legislators are called "senators."
Nebraska didn't start out as a unicameral legislature. Until 1935, the state followed the same bicameral model as other US states.
In the early 1930s, U.S. Senator George W. Norris advanced the argument that a unicameral legislature would benefit Nebraska in two ways. First, it would be less expensive. Second, it would result in more effective representation for the citizens of Nebraska. The unicameral legislature was passed by popular vote in 1934 and was seated for the first time in 1935.
Currently, Nebraska's legislature seats 49 senators, who each serve for four years. Each senator represents about 35,000 state citizens.
Another unusual feature of Nebraska's legislature is that it is, officially, nonpartisan. While individual senators may hold views that align with those of one or another political party, senators do not run as members of a particular party, and no party affiliation is listed on the ballot. To understand what each candidate supports and believes, Nebraskans must look into the candidate's particular platform, rather than relying on party affiliation.