"km distance" refers to the measure of the amount of space between two points, such as two cities or places, using kilometers as a unit of measurement. It tells you how far apart two points are from each other in kilometers. Full definition
I managed to complete the 5 km distance in 30 minutes and didn't stop to walk once! (blog.sa-venues.com)
A knee injury right before the event kept her from completing the walk, but she still managed to do a challenging 50 km distance during her training. (remonline.com)