How much weight will a 20ft long piece of 2X6 lumber support support?

The weight a 20-foot long piece of 2x6 lumber can support depends on several factors, including the type of wood, its moisture content, and how the load is applied. Generally, a 2x6 made of common structural lumber like pine can support approximately 1,000 to 1,500 pounds when properly supported at both ends and loaded uniformly. For specific applications, it's important to consult building codes and possibly a structural engineer to ensure safety and compliance.