And, for most of U.S. history, the court, like the country, was dominated by Protestant Christians. But today, it is predominantly Catholic and Jewish.
It has become more conservative and is about to get even more so with President Trump's expected pick to replace Justice Anthony Kennedy, who is stepping down from the court at the end of July.
Everyone on President Trump's shortlist, but one, is Catholic. So what, if anything, do the current justices' and potential nominees' faiths tell us — and how has the religious make up of the Supreme Court changed?
"It's extraordinary and unprecedented in American history," said Louis Michael Seidman, a constitutional law professor at Georgetown University, which is affiliated with the Catholic Church. "There was a time when, for example, there was tremendous anti-Catholic bias ... and, of course, there was a time when there was a lot of anti-Semitism, and a lot of that has gone away."