The election districts for each state legislature and the United States House of Representatives are determined by the state legislature in each individual state. The election districts are drawn every 10 years.
They are always elected by the people for the Senate and The House of Representatives.
This is a bad question because it implies a change took place. In fact, the way House of Representatives legislatures were chosen has always been the same: "House of Representatives shall be composed of Members chosen every second Year by the People of the several States." Article I, Section II
Thomas Jefferson's first term and the election of John Quincy Adams were determined by the House.
multiparty districts
When voting for the representatives for the House, the state gets divided into several districts. They are divided so that each district all has almost the same population. Each districts then vote for one representative, and the candidate who wins becomes one of the representatives for that state. So basically, the candidates that are running are not getting votes from the whole state but only in that one district that they're from.
The last election for the representatives was in 2003
Under the Constitution, state legislatures chose the US Senators for their state. Until the passage of the 17th Amendment in 1913, state legislatures were the bodies who determined how senators were chosen. Some states and territories had already enacted popular election prior to the amendment's passage.
single member districts
Representatives in the U.S. House of Representatives are elected for two-year terms by the voters in the legislative districts in each state. Representatives serve a two-year term of office, and all 435 seats come up for election at once, in even-numbered years.
Through an Electoral process. Voters in each Representative's district vote for their preferred candidate. There are 435 representatives apportioned between each state according to population every 10 years. The constitution says no more than one rep. for every 30,000 people, but with our population being so big, we had to limit the number of reps, so now they each represent around 650,000 people.
Early in the history of the United States, US Senators were elected by their state legislatures. This was seen as one of the important differences between the Senate and the House of Representatives. This method of election appeared in Article 1, Section 3 of the US Constitution. Direct election of US Senators became the norm in all states during the 20th century with the passage of the 17th amendment in 1913.
With an estimated population of 11.54 million, Ohio has 16 congressional districts. There are 435 congressional districts in the United States.