The Head of the River Race (HORR) is an against-the-clock ('processional') rowing race held annually on the River Thames in London, England between eights, other such races being the Schools' Head of the River Race, Women's Head of the River Race and Veterans' Head of the River Race. Its competitors are, with a few experienced junior exceptions, seniors of UK or overseas competitors and it runs with the ebb tide down the 4.25 mile (6.8 km) Championship Course from Mortlake to Putney which hosts the Oxford and Cambridge head-to-head races usually between one and two weeks later.