Аccording to the 2020 Bulgarian census, Rasnik has a population of 399 people with a permanent address registration in the settlement.

Rasnik village lies between the plain Bazglav and Viskyar mountain, at an average elevation of 782 meters.

The first written data confirming the existence of Rasnik dates back to the 16th century.

There are remains of an ancient Roman road near the village.

The name Rasnik stems from the fact that once in the area of the village the verdure was thriving.