It's a road rally on foot. It's a treasure hunt in the woods. It's finding your way from one bright colored marker (control point) to another using a map and compass. The topographical map shows trails, roads, open areas, fences, buildings, and more. They all indicate where to find a control point.
Orienteering is a special kind of sport that attracts both competitive and recreational participants. Scouts, backpackers, and those who enjoy walking find it good practice in using map and compass. Some enjoy the competitive side, trying to finish as quickly as possible, testing their endurance as well as their ingenuity. Others like the noncompetitive side of it and use it as an excellent excuse to walk in the woods, content to find all the points while enjoying the beauty of nature.
The basics can be learned in half an hour, but you can spend a lifetime honing your skills. The equipment is simple and inexpensive, the necessary conditioning modest, the primary skill easy, and the rewards many.
Orienteering challenges the mind and the body. The key is more the ability to make wise decisions rather than the ability to run like a deer. Hence the name, "THE THINKING SPORT". On the course you must make decisions and calculations, i.e. reading the map, recognizing the terrain, and choosing routes. For the more advanced courses, you will set your compass and occasionally count paces.
This mental challenge make Orienteering consistently stimulating. The best part of Orienteering is sharing a common, yet individual experience.
Here is a good Video you should watch that tells you more about Orienteering.