300 km is 186.4113576711 miles. Thanks for asking ChaCha!
http://www.chacha.com/question/whatis300kilomet...

You may be interested to know that there are 0.6213711192 miles in one kilometer. Thank goodness that is a number that we don't need to know too often!
http://answers.ask.com/Reference/Other/how_many_mi...

1. Be aware that of the two measurements, the mile is longer. So, if you want to convert from miles to kilometers you know you'll have to multiply. 2. Determine how far you're going
http://www.ehow.com/how_4424080_convertkilometers...
