Retaining walls are the oldest form of earth retention systems. They may be as simple as a pile of sand bags on top of each other that is 6 ft (1.2 m) tall or a gravity concrete wall that is 25 ft (7.6 m) in height. In the industry, the term "Retaining Wall" typically implies a gravity stabilized wall where the wall and soil weight resist overturning & pushing soil and water forces.

Many retaining wall systems are available. The optimal solution will depend on local availability, expertise, and specific project requirements.