The David Nicholson Mares' Hurdle, currently known for sponsorship purposes as the Close Brothers Mares' Hurdle, is a Grade 1 National Hunt hurdle race in Great Britain which is open to mares aged four years or older. It is run on the Old Course at Cheltenham over a distance of about 2 miles and 4 furlongs, and during its running there are ten hurdles to be jumped. The race is scheduled to take place each year during the Cheltenham Festival in March.