"The Red Planet and the Earth have not been so close since 2003, and will not be again until 2035," NASA said.
Astronomers from around the world trained their telescopes in the sky on July 31, when the red planet was 35.8 million miles (57.6 million kilometers) away.
A popular point of public observation was the Griffith Observatory in Los Angeles, where Mars was visible to the naked eye as a bright orange spot in the sky, according to a live broadcast held to commemorate the celestial event.
"Mars is invading us tonight," said observatory director Ed Krupp.
The closest point to Earth in the elliptical orbit of Mars arrived at around 1100 GMT on Tuesday, NASA said.
Astronomers are interested in the travel route of Mars because it helps decide the best times for the launch of the spacecraft.
When the Sun, Earth and Mars align, with the Earth in the middle, a phenomenon called "opposition" occurs, which provides the brightest view of Mars.
But also, "at the time of the opposition, a planet is at its closest distance to Earth during a given year," the US space agency explained.
Since Earth and Mars are aligned in opposition approximately every two years, "this is the reason why most of NASA's missions to the Red Planet are separated at least two years, to take advantage of the closest distance "
The close approach this year is not a record.
The minimum distance from Earth to Mars is approximately 33.9 million miles (54.6 million kilometers), and is rarely achieved.
The last closest approach was in 2003, when Mars was 34.6 million miles (55.7 million kilometers) from Earth "and the closest it had been in nearly 60,000 years," NASA said.
Another close encounter like that of 2003 will not happen until the year 2287.
For those who missed the closest approach, do not worry. Mars will remain visible in the night sky for the next few months.