One bowling crease is drawn at each end of the pitch such that the set of stumps fall on it (and consequently it is perpendicular to the imaginary line joining the centres of both middle stumps). Each bowling crease should be 8 feet 8 inches (2.64 metres) in length, centred on the middle stump at each end and terminating at one of the return creases.
The bowling creases lie 22 yards (66 feet or 20.012 m) apart and mark the ends of the pitch, and so may be used to determine whether there is a no ball because a fielder has encroached on the pitch or the wicket-keeper has moved in front of the wicket before they are permitted to do so.
Formerly, part of the bowler's back foot in the delivery stride was required to fall behind the bowling crease to avoid a delivery being a no ball. This rule was replaced by a requirement that part of the bowler's front foot in the delivery stride must fall behind the popping crease (see below).
Read more about this topic: Creases