A horse race is a contest in which horses compete for the best time around a course of jumps or on the flat. The horses may be ridden or driven and a wide variety of tack is used. Spectators place bets on the outcome of a race, and winning horses often receive substantial prize money, which is known as a purse. The sport has a long history and is popular in many nations. It is regulated by the government in some countries, while in others it is overseen by private agencies. In England the Jockey Club is responsible for setting long-term policy, and in most other nations racing is governed by state agencies or national governing bodies.

Horse races were originally contested over natural terrain, with the course marking out a series of hills and valleys. The steeplechase, which involves jumping over a number of obstacles, is considered the most arduous and dangerous of these kinds of races. The Greek author Xenophon referred to this type of competition in the 5th century bc, and it was long a favorite sport of cavalry officers.

In the United States, organized racing began with the British occupation of New Amsterdam in 1664. Colonel Richard Nicolls laid out a two-mile track and offered silver cups to the winners of spring and fall races. The early American Thoroughbreds were larger and more mature than those of Britain, and the sport emphasized stamina rather than speed. The Civil War brought a demand for fast horses, and Union officials steadily imported thoroughbreds from England.

The length of a race varies by country and is based on custom. In the United States, most races are run over a mile (2.4 kilometers) and have two turns. European races are usually longer, with some of the classics such as the Prix de l’Arc de Triomphe in France and the Caulfield and Sydney Cups in Australia taking place over 21/2-mile courses.

Modern races are regulated by law to ensure fairness and transparency. In most of the world, horse races are conducted in pari-mutuel betting, a system in which bettors pay into a common pool and share the winnings with the track’s management. In addition, a minimum amount must be placed by all entrants before the race begins.

Horse racing has a long tradition of promoting itself as a glamorous, exciting sport. But it has also been a source of much scandal, most recently in the form of accusations that it promotes doping. The sport has made some commendable efforts in recent years to improve safety for the horses, but it will never be able to eliminate danger entirely.

The number of people who attend horse races is declining. Older fans tend to stay loyal, but new would-be fans are turned off by the constant news of accidents and injuries and by the sport’s doping problems. Many people are also turning to other gambling activities, according to a study by IBISWorld.