There is a 5-kilometer-wide body that revolves around the sun in pace with Earth, on a 364 days a year. Its closest approach to Earth is 12 million kilometers. Technically it does not orbit the earth, but rather the sun, and as such it is not a moon.
It is called Cruithne 3753
Cruithne is technically, a trojon, meaning it follows the host planet (Earth) and its orbit, though they are not identical. Other planets have Trojans, such as Saturn, which has hundreds of thousands..