Hi!
Pluto is the farthest planet from the sun. Its average distance from the sun is 3,670,050,000 miles (5,906,380,000 kilometers). Because Pluto has an orbit that is very elliptical, there is a big difference between its closest distance to the sun and its farthest distance from the sun. The closest Pluto gets to the sun is 2,756,902,000 miles or 4,436,820,000 kilometers. The farthest Pluto gets from the sun is 4,583,190,000 miles or about 7,375,930,000 kilometers. (from
http://coolcosmos.ipac.caltech.edu/cosmic_kids/AskKids/pluto_distance.shtml)
HOWEVER! You may have heard about a new "planet", Sedna, which is three times further away than Pluto. Check out
http://www.nineplanets.org/sedna.html for more information!
cheers,
Sarah