The 19th Amendment to the United States Constitution guarantees all American women over the age of 18 the right to vote. It was passed by Congress on June 4, 1919, but it wasn't until Tennessee passed the amendment more than a year later on Aug. 18, 1920, that it finally received the approval of three-fourths of the states it needed to become official.
The women's rights movement came to national prominence in 1848. The original women's voting rights amendment was first presented to Congress in 1878, but it took decades of petitions and protests before women would finally win the right to vote.
In the more than 70 years passed between the first women's rights campaigns, most of the original campaigners passed away and weren't able to see their hard work finally pay off. Still, some of them, such as Susan B. Anthony, are still remembered today.
Even though women didn't get the right to vote nationally until 1920, 21 states had already passed laws to allow women to vote in state and local elections. The first state to do so was Wyoming, which gave women the right to vote when it was still a territory in 1869, 21 years before it became a state.