The US has had 225 mass shootings in 2021 so far. Here's the full list.

• The Gun Violence Archive counted 225 shootings in the US in 2021 as of May 28.
• More than 17,000 people in the US have died so far in 2021 from gun-related violence.
• The US is on track to have more shootings in 2021 than any recent year on record.

When the White House went to lower its flags to honor the 10 people shot dead at a Colorado supermarket on March 23, staffers realized their work was already done: The flags were still lowered from a shooting less than a week prior.

The US's relatively unusual gun protections baked into the Constitution have created a murky relationship between firearms and American citizens. Some states have restrictive gun laws, while others have more relaxed regulations, allowing for greater rates of ownership for hunting and protection.

But firearms have become one of the leading causes of death for Americans of all ages and the second-leading cause of death for children under the age of 19, according to the Giffords Law Center, a gun-safety organization.

According to the Gun Violence Archive, a nonprofit that tracks shootings in the US, there have been 225 mass shootings in 2021 alone - and that tally does not appear to be slowing down anytime soon.

This table includes the names, locations, and casualty information from each mass shooting in the US so far. We're keeping it updated periodically as more incidents occur.

Read more: There have been 366 mass shootings in the US so far in 2019 - here's the full list

'Mass shooting' has different definitions

The definition of a mass shooting differs from source to source, but the Gun Violence Archive defines a mass shooting as a single incident in which four or more people are shot (not counting the shooter) in the same incident in roughly the same time and place.

The Congressional Research Service does not have an official definition for a mass shooting but instead relies upon the definition of a "mass killing" as "three or more killings in a single incident" that was included in the Investigative Assistance for Violent Crimes Act of 2012 that became law in 2013 after a gunman killed 27 kids at Sandy Hook Elementary School in Connecticut.

According to data from the Gun Violence Archive, more than 15,299 people have already died this year from gun-related violence, with an additional 12,531 gun-related injuries.

There have been significantly more mass shootings in 2021 than in 2018, 2019, and 2020

Historically, mass shootings are more likely to occur in the latter half of the year

You can view a report of any incident by visiting the list on the Gun Violence Archive's website.

Correction: The Gun Violence Archives defines a mass shooting based on the number of people shot in a single incident. An earlier version of this article incorrectly stated the definition was based on the number of people killed.