The easiest way to find a trade association is to search the name of your industry OR the name of the industry and a location. Many national association have local (state, regional) chapters. These local chapter make it easier to meet people in your region and discuss local issues about your industry. Almost every industry and sub-industries have trade associations,
State Association (examples)
National Association with Local Chapters (examples)
Trade associations are a great resource for learning about an industry, networking, research, and keeping current. Plus, you can learn from seasoned professionals in these industries.