What is the largest Planet known to man?

It is the Jupiter from outer space. And the years from 170 light years away from the Earth.

The planet, dubbed HAT-P-1, is located some 450 light-years from Earth in the constellation Lacerta. It is the largest planet ever discovered and boasts a radius nearly 1.4 times larger than Jupiter's. HAT-P-1 is also the least dense of all known planets.