This weekend is President's Day, which is usually a cause of celebration in the United States, but may not be as joyous this year. Still, our country has a rich history of incredible leaders who helped get the nation to where it is today. And a lot of those great leaders used marijuana.

Here are 12 presidents we know used marijuana.

1. Barack Obama

President Obama admitted to using marijuana, as well as cocaine, in his memoir Dreams from My Father. And considering some of the minor changes he made to enforcing cannabis laws in the final years of his presidency, he may be the most pro-marijuana president yet. (Although that's not saying much.)

2. George W. Bush

The younger Bush president was recorded unknowingly while admitting to use marijuana. He's also admitted to using cocaine and having a drinking problem during his younger days. However, Bush also said he didn't want people to know about his cannabis use because kids might use that as justification for their own use.

3. Bill Clinton

Clinton famously said that while he did try marijuana, he couldn't "didn't inhale." Although some of his classmates said that's mostly because he preferred using edibles.

4. John F. Kennedy

JFK used several substances throughout his life to deal with a back injury he sustained while serving during World War Two. A biography on the president claimed he used marijuana while in the White House to help deal with those injuries.

5. Franklin Pierce

Our 14th President Franklin Pierce lived in an era where marijuana was just another plant that no one thought too much about. While serving in the Mexican-American war, Pierce wrote in a letter that smoking marijuana was the only good thing about his time in combat.

6 and 7. Zachary Taylor and Andrew Jackson

While there isn't much documented proof, it's been argued by historians that Taylor and Jackson both smoked marijuana alongside their troops during their time in the military.

8. James Monroe

Before serving as our fifth president, Monroe served as ambassador to France, where he openly smoked hashish. He supposedly continue doing so all the way until his death.

9. James Madison

Madison once said that hemp inspired him to write our nation's Constitution. While some have argued that Madison was simply referring to the industrial version of the plant grown by American colonists, others claim he may have used the drug for a little "creativity" while writing the document.

10. Thomas Jefferson

Technically, there isn't any documented proof that Jefferson used marijuana. However, we do know he was a hemp farmer and historians have suggested he did grow his own personal stash of the plant. What on earth could he have been using it for?

11. John Adams

Adams was perhaps the first marijuana advocate in America. In a newspaper editorial, he wrote, "We shall by and by want a world of Hemp more for our own [consumption]."

12. George Washington

Yes, our nation's father has a history with marijuana. Like Jefferson, Washington was also a known hemp farmer. In a letter he wrote, “Began to separate the male from female plants rather too late…Pulling up the (male) hemp. Was too late for the blossom hemp by three weeks or a month.” Many have interpreted this letter as meaning he was trying to cultivate the female plants to have a higher THC content.

(h/t French Toast for information)