Voting age history by state...

 The minimum voting age in the United States is set nationally at 18 years old under the 26th Amendment, ratified on July 1, 1971, though individual states held sole authority over voter qualifications and traditionally maintained a limit of 21 for much of American history. [1, 2]

Early History and the Age of 21

• Founding Era (1788 onwards): The original U.S. Constitution did not establish a federal voting age, leaving qualifications entirely to the states. Most early states adopted the English common law standard, limiting suffrage primarily to white male property owners or taxpayers aged 21 and older. [1, 2]
• Abolition of Property/Religious Tests (1820s–1850s): States gradually dropped religious and property ownership prerequisites, standardizing the age requirement at 21 for white males, later expanded by the 14th and 15th Amendments (post-Civil War) and the 19th Amendment in 1920 for women. [1, 2]

Early State-Level Exceptions (1940s–1950s)

Before 1971, a small number of pioneer states independently lowered their state-level voting ages, driven largely by the wartime argument that citizens old enough to be drafted into military service should have a voice in elections. [1, 2]

• Georgia (1943): Became the first state to lower its minimum voting age to 18 via a constitutional amendment and public referendum, popularized by the slogan "old enough to fight, old enough to vote".
  [1, 2]
• Kentucky (1955): Amended its state constitution to lower the voting age to 18. [1]
• Alaska (1959) and Hawaii (1959): Entered the Union as states with voting ages already set below 21 in their foundational state constitutions. [1]
• Other states: By 1970, a handful of other jurisdictions had permitted lower ages or partial exceptions, while most held fast at 21. [1, 2]

Federal Intervention and the 26th Amendment (1970–1971)

• Voting Rights Act Amendments of 1970: Congress passed statutory changes lowering the voting age to 18 for all federal, state, and local elections. However, in the Supreme Court case Oregon v. Mitchell (1970), the Court ruled that Congress had the power to set the voting age for federal elections, but individual states retained the right to set it for state and local elections.
• Ratification of the 26th Amendment (1971): To prevent administrative chaos and dual-age voting systems across the country, Congress proposed the 26th Amendment in March 1971. It achieved rapid ratification by the required three-fourths of state legislatures in record time, officially securing the uniform voting age of 18 nationwide. [1, 2, 3]

Modern State Nuances (Current Practice)

While the baseline minimum age is 18 for general elections, state laws continue to govern ancillary rules: [1]

• Primary Voting for 17-Year-Olds: In a majority of states, state law permits 17-year-olds to vote in primary elections and caucuses if they will turn 18 on or before the date of the corresponding general election.
• Municipal Voting at 16: A select number of local jurisdictions across states like California, Maryland, Vermont, and New Jersey have extended local or school board voting rights down to 16-year-olds for specific municipal matters. [1]