The Supreme Court decides fewer than 100 cases a year, and most of them never make the evening news. A small number, though, change the country in ways that last for generations. These landmark Supreme Court cases shaped how the government works, what rights people have, and how Americans live day to day.

What Makes a Supreme Court Case a Landmark
A landmark case is one that sets a major new rule or overturns an old one. It usually affects far more people than the parties who brought the lawsuit. Some landmark cases expanded rights, some limited government power, and a few are now remembered as serious mistakes.
Knowing these cases also helps you follow current debates. When people argue about a new ruling, they’re almost always pointing back to one of these decisions. Here are the famous Supreme Court cases worth knowing, in the order they were decided.
Marbury v. Madison (1803)
This is the case that gave the Supreme Court much of its power. William Marbury sued because his appointment as a justice of the peace wasn’t delivered before President John Adams left office. Chief Justice John Marshall ruled that the law Marbury relied on was unconstitutional, and in doing so, he established judicial review, which is the power of courts to strike down laws that conflict with the Constitution.
McCulloch v. Maryland (1819)
Maryland tried to tax the Second Bank of the United States, and the bank’s cashier, James McCulloch, refused to pay. The court ruled that Congress had the power to create the bank even though the Constitution doesn’t mention banks, thanks to the Necessary and Proper Clause. It also held that states can’t tax the federal government, which strengthened federal power for good.
Dred Scott v. Sandford (1857)
Dred Scott, an enslaved man, sued for his freedom after living in free territory. The court ruled against him, holding that Black Americans weren’t citizens and couldn’t sue in federal court. It’s widely considered the worst decision in the court’s history, and it helped push the country toward the Civil War before the 14th Amendment overturned it.
Plessy v. Ferguson (1896)
Homer Plessy challenged a Louisiana law requiring separate railroad cars for Black and white passengers. The court upheld the law and created the “separate but equal” doctrine. That ruling gave legal cover to segregation across the South for more than half a century.
Brown v. Board of Education (1954)
In a unanimous decision, the court ruled that segregated public schools were unconstitutional. Chief Justice Earl Warren wrote that separate educational facilities were inherently unequal. Brown overturned Plessy in public education and became a cornerstone of the civil rights movement.
Gideon v. Wainwright (1963)
Clarence Earl Gideon was charged with a felony in Florida and couldn’t afford a lawyer, so he defended himself and lost. From prison, he wrote a handwritten petition to the Supreme Court. The court ruled that states must provide lawyers to criminal defendants who can’t afford one, which is why public defenders exist today.
Miranda v. Arizona (1966)
Ernesto Miranda confessed to a crime without being told he had the right to stay silent or talk to a lawyer. The court ruled that police must inform suspects of these rights before a custodial interrogation. That’s where the famous Miranda warning comes from, and you’ve heard it in just about every cop show ever made.
Loving v. Virginia (1967)
Richard and Mildred Loving, an interracial couple, were convicted under Virginia’s ban on interracial marriage. The court unanimously struck down the law, holding that marriage is a fundamental right. The decision ended bans on interracial marriage nationwide.
Tinker v. Des Moines (1969)
Students in Iowa were suspended for wearing black armbands to protest the Vietnam War. The court ruled that students don’t lose their free speech rights at school, as long as their speech doesn’t substantially disrupt the school. It’s still the key case on student speech today.
United States v. Nixon (1974)
During the Watergate scandal, a special prosecutor subpoenaed tapes of President Richard Nixon’s White House conversations. The court ruled unanimously that executive privilege isn’t absolute and ordered him to turn them over. Nixon resigned just over two weeks later.
Obergefell v. Hodges (2015)
This case combined challenges from same-sex couples in several states. The court ruled that the Constitution guarantees same-sex couples the right to marry. It made marriage equality the law nationwide.
Why These Cases Still Matter
Landmark cases aren’t just history lessons. They’re the foundation for arguments lawyers make in courtrooms today, and they shape the rights you probably take for granted. Some of them were reversed later, which is a reminder that the court’s view of the Constitution can change over time.
If one of these cases caught your interest, it’s worth reading the actual opinion. Many are shorter and more readable than you’d expect, and the reasoning often tells a better story than any summary can. You’ll come away understanding the country a little better.