Cross-country running is a sport in which teams of runners compete to complete a course over open or rough terrain before other teams. It differs from road running or track running principally in the course, which may include grass, mud, woodlands, or water, and in its scoring system. Teams are composed of between five to seven runners. It is one of the most popular praticipanary sports, and usually takes place in the fall/winter.

Cross-country running was originally an English sport created in the early 1800's. However, the sport was entirely different and known as "the paper chase". The original sport had a group of runners run along a randomly-picked course and drop paper markers on the ground as they ran along. Another group of runners would then give chase to the former, following the paper trail left behind. This sport was played mainly by colleges, such as Cambridge and Oxford.

Over time, however, the sport progressed into the sport that it is today. In 1878, the sport was introduced into the United States by William C. Vosburgh. At first, the sport served mainly as a training season for the more well-known sport of track and field. Nine years later, cross-country running became a formal sport in the United States. Despite the international popularity of cross-country, the sport was dropped from the Olympics after 1924 due to it being an inappropriate summer sport. In the 1960's, the International Amateur Athletic Federation, which regulates cross-country running, allowed women to run for the first time.

Each cross-country running course is different in composition. Distances are generally standardized in leagues, however there will be little in common between any two courses other than their distance. As such, accurate comparisons cannot be made between performances on different courses. For this reason, records of the fastest times in international competition are not kept.

Races are started by having each team move into its own "box" along the start line. A gun or horn is then sounded, and runners have a few hundred meters to condense from the wide starting line into the much narrower path that must be followed until the finish.

The runner is responsible for staying within a specified distance of the marked path. Courses may be marked in various methods. A common method is to attach to poles colored flags which communicate direction. A red flag means left, a blue flag means straight, and a yellow flag means right. Flags must be passed on the opposite side of the direction to which the runner is turning, with the exception that blue may be passed on either side. Ground markings are also used, usually a solid painted centerline.

The course usually ends at a finish line located at the beginning of a chute. The chute is a long, roped walkway that keeps athletes single-file in order of finishing. Less common is an open finish line. This usually involves reading radio-broadcasting computer chips attached to each runner. Prior to the finish line, the course typically widens to allow more passing.

In amateur international competition, the International Amateur Athletic Federation requires a minimum 2,000 m to 5,000 m (1.25 to 3.1 miles)for females and 12,000 m (7.5 miles) for males.

Distances in United States amateur running differ based on gender and league. In grammar school (elementary school in US; most such schools do not have school teams, but many running clubs exist for youth runners (including the Junior Olympics)) cross country, the courses are around 1.5 miles or 2,400 m in length and include less challenging terrain then in the more advanced leagues. In secondary schools, the standard male and female varsity distance is 5,000 m, or approximately 3.1 miles. The U.S. Nationals are 5,000 m as well. However, states differ in their regulations, and in some this may be reduced to 2.5 miles for females or junior varsity males. At the university level, distances are 5,000 m or 6,000 m for females and 8,000 m or 5 miles for males for most invitationals and NCAA Division III regional and national meets. For NCAA Divisions I and II, men race 10,000 meters and women 6,000 meters at regional and national competitions. The largest cross country invitational in the world is at Mt. SAC.

In the US, cross-country running is normally scored on a team basis. Points are awarded to individual runners equal to the position in which they cross the finish line. Only the first five on each team are counted towards that team's score. The sixth and seventh runners on each team are called "pushers" or "displacers," because while they do not earn points for their team, they push up the point score of each opponent after them. No runners after the first seven per team count in the scoring in most cases. Teams are awarded ranks based on the number of points their top five runners have, with lowest being best. The rules in the event of a tie vary depending on the competition. Often, the team which has a lower sixth-place runner is the winner. However, in the NCAA, the sixth runner is not used and ties are possible.

The lowest possible score is a 15 (1+2+3+4+5), achieved by a team's runners finishing in each of the top five positions. The opponents would have a score of 40 (6+7+8+9+10), which is considered a "sweep" for the winning team. Of course, if the winning team's 6th and 7th runner's came in 6th and 7th, the opponent's score would be a whopping 50 (8+9+10+11+12). Accordingly, the official score of a forfeited dual meet is 15-50.

Notable cross-country athletes include Kenenisa Bekele, an Ethiopian who won the gold medal at the 2004 Olympics in the 10km event and the silver medal in the 5km, has done the double of winning the short course and long course at the World Cross-Country Championships four years in a row. Many notable United States track and field distance athletes were high school cross country runners, including Jeff See national sophomore class mile record holder and Olympic 10,000 meter champion Billy Mills, the late Steve Prefontaine, and Erik Woodward. Outstanding American cross-country runners also include Don Lash, who won seven consecutive national championships from 1934 to 1940, and Pat Porter, who won eight titles from 1982 to 1989.

• History of Cross-Country Running
• U. S. Cross-Country Championships
• Dyestat.com-national records of cross-country and track