How long can a single axle trailer be?

A single axle trailer can be up to 75 feet in length. The length depends on state. In California, the total length is usually 65 feet. The trailer length is 28 feet 6 inches and the motorized house length is 40 feet (38 feet if the trailer has a single-axle fifth wheel, and 40 feet if there are two or more axle fifth wheel). The width is 102 inches (excluding safety equipment and RV devices up to 6 inches).