Electoral system for national legislature

United States of America, Mid-Term Congressional Elections, 8 November 2022, ODIHR Needs Assessment Mission Report, accessed 26 October 2022

“Senators and Representatives are directly elected, primarily through first-past-the-post contests. Senators are elected to six-year terms, with approximately one third of senate seats contested for every two years. Elections for all 435 congressional seats are held every two years. Senate electoral districts correspond to the entire state, and Representatives are elected from single-member districts.”