<P> Voter registration in the United States takes place at the county level in many states and at the municipal level in several states, and is a prerequisite to voting at federal, state and local elections . The only exception is North Dakota, which does not require registration, although North Dakota law allows cities to register voters for city elections . The majority of states set cutoff dates for voter registration, ranging from 2 to 4 weeks before an election; while a third of states have Election Day or "same - day" voter registration which enables eligible citizens to register or update their registration when they vote before or on Election Day . </P> <P> It has been argued that some registration requirements deter some people (especially disadvantaged people) from registering and therefore exercising their right to vote, resulting in a lower voter turnout . According to a 2012 study, 24% of the voting - eligible population in the United States are not registered to vote, equaling some 51 million U.S. citizens . While voters traditionally had to register at government offices by a certain period of time before an election, in the mid-1990s, the federal government made efforts to facilitate registering, in an attempt to increase turnout . The National Voter Registration Act of 1993 (the "Motor Voter" law) now requires state governments to either provide uniform opt - in registration services through drivers' license registration centers, disability centers, schools, libraries, and mail - in registration, or to allow Election Day voter registration, where voters can register at polling places immediately prior to voting . In 2016, Oregon became the first state to make voter registration fully automatic (opt - out) when issuing driver licenses and ID cards, since followed by four more states . Political parties and other organizations sometimes hold voter registration drives to register new voters . </P> <P> In most states, persons registering to vote may at the same time declare an affiliation with a political party . </P>

How many are registered to vote in the us
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