Stephanie Marie Herseth Sandlin is an American attorney, university administrator, and politician from the Democratic Party. She represented South Dakota's at-large congressional district in the United States House of Representatives from 2004 until 2011. Sandlin was first elected to Congress in a July 2004 and won three full terms before losing to Republican Kristi Noem in 2010. She was the youngest female member of the House, and the first woman elected to the House from South Dakota. Before her 2007 marriage to Max Sandlin, she was known as Stephanie Herseth. She is a Democrat and a member of the Herseth family of South Dakota. She and Senator Tim Johnson are the last Democrats to win a statewide and/or federal election in South Dakota.

South Dakota's at-large congressional district is the sole congressional district for the state of South Dakota. Based on area, it is the fourth largest congressional district in the nation.