Neptune's distance from the sun is 2.795 billion miles. That is the furthest planet from the sun.
This is Neptune from a giant telescope. The planet is made mostly of gasses and ice, this is why Neptune is blue.
Interesting facts : In the solar system Neptune is the forth largest planet in diameter. Neptune is the third most massive planet. It has 17 times more mass then the earth.
Sources: Sarfri, Spacefacts.com, planetforkids.org, Nasa.gov