The answer to 'retaining wall installation cost' is that the cost can vary widely depending on several factors. Typical ranges for retaining wall installation can be $15 to $50 per square foot, but the final price will depend on the materials used, the size and complexity of the project, site conditions, and your location.
Factors that influence the cost include the type of retaining wall (concrete, stone, brick, etc.), the height and length of the wall, any necessary excavation or site preparation, and the labor costs in your area. Taller walls or walls with a lot of curves or corners will generally cost more. It's essential to get multiple local quotes to understand the typical pricing in your region.