Another name for the North Star is Polaris.
It is a pole star, which means that it's aligned with the earth's axis of rotation so that it appears to be overhead when viewed from the North Pole. This position is called the north celestial pole. The other stars in the northern hemisphere appear to rotate around it.
Because of its fixed position the North Star has been used since ancient times as a navigational guide both on land and sea.
Polaris is at the end of the Little Dipper's handle, and is in line with the two stars that make up the outer side of the Big Dipper. This makes it easy to locate in the night sky.
As you move to lower latitudes Polaris appears lower in the sky, and it isn't visible from the Southern Hemisphere.