Theresa Greenfield is challenging GOP Sen. Joni Ernst for US Senate in Iowa.
Polls in Iowa closed at 9 p.m. local time and the results are rolling in, says Business Insider.
Ernst is an Iowa Army National Guard veteran and was first elected to the US Senate in 2014.
Theresa Greenfield is an urban planner, real estate developer, and first-time political candidate.
Ernst serves on the Senate Committee on the Judiciary, Armed Services, and Environment and Public Works.
Currently, the US Senate is made up of 53 Republicans, 45 Democrats, and two independents.