The administration of elections in the United States—including elections for federal office – is highly decentralized.
Fundamental election law decisions – such as registration and voter identification requirements, and early in-person voting and vote-by-mail rules – are made by the state legislature, but the actual conduct of elections is handled almost entirely by local governments.
Local officials register voters, process absentee ballot applications, design ballots, recruit and train poll workers, manage early voting and election day operations, acquire, maintain and secure voting equipment, and count, canvass, and report the results. In most states, local officials also pay for most of the costs.
Election Law | Law
Richard Briffault, The Promise and Peril of Local Election Administration, Reg. Rev. (September 27, 2021), https://www.theregreview.org/2021/09/27/briffault-promise-and-peril-of-local-election-administration/