There are plenty of regional organizations for contractors across the United States. However, there are very few national organizations that work for contractors throughout the nation. There are a few, though. Here are the top three nationwide general contractor associations.
1. The Associated General Contractors of America
The Associated General Contractors of America is the largest nationwide association for general contractors in America. Headquartered in Washington, D.C., it has 95 state and local chapters across the country. The group provides all of the services necessary to improve the quality of the contracting industry and to protect the public interest.
This group was founded in 1918 via a request from then-U.S. president Woodrow Wilson. Wilson wanted an organization that represented the construction industry in the United States that the government could partner with to build and improve the infrastructure of the nation. The establishment of the Associated General Contractors of America fulfilled this goal, and the organization has remained true to its founding principles ever since.
There are over 30,000 contracting firms in the United States that are members of this organization. The group helps contracting firms all over the country improve and expand their scope of business. This leads to more jobs and nationwide economic growth. The Associated General Contractors of America is the voice of the construction industry in the United States, and any serious contracting company would do well to become a member.
2. National Association of Minority Contractors
The National Association of Minority Contractors has many local chapters across the United States, with its national headquarters being in Washington, D.C. It has a long history of assisting minority contractors in increasing their visibility and legitimacy in the construction industry.
Founded in 1969, this organization helps minority contractors by giving them a forum where they can share information and support each other. They can also band together through the national organization to make their voice heard nationwide. The group is active in efforts to remove barriers to entry for minority contractors and to gain more opportunities for access for these contractors in the construction industry. The group is open to people of all races and ethnicities. However, its main efforts focus on helping African American, Native American, Hispanic American, and Asian American contractors.
3. Associated Builders and Contractors
The Associated Builders and Contractors has 22,000 members from more than 19,000 construction and contracting firms. Founded in 1950 and based in Baltimore, Maryland, this organization is 
based on the merit philosophy that work should go to the most qualified lowest bidders on any project. The group and its 72 chapters across the country help their members get work based on this philosophy and provide them with the tools to deliver the work on time and safely.
The group lobbies in Washington, D.C. on behalf of the industry and helps its members deal with industry-wide issues. Other activities in which the group is involved to help its members get work in a fair and ethical manner are legal advocacy, education, national and chapter awards programs, employee benefits, best practices, technology, and promoting business development through an online contractor directory.