Hemp is useful in a variety of ways. Today, however, Hemp is highly controversial because it looks a lot like the Marijuana plant. United States policy doesn't consistently distinguish between Hemp and the drug plant. This means that the US for the most part, misses out on growing one of the most productive and versatile plants in the world.
In fact, over 25,000 products can be made out of hemp. George Washington and Thomas Jefferson both grew hemp and Ben Franklin actually owned a mill that made hemp paper. It was on hemp paper that Jefferson wrote the Declaration of Independence.
It used to be widely grown in the U.S., because the canvas and rope for ships was made out of hemp. Hemp is even able to be applied to cars. Rudolph Diesel designed his engine to run on hemp oil.
Henry Ford experimented with hemp to build his car bodies, because he wanted to build and fuel cars from farm products. Hemp oil used to grease machines and paints, shellacs, resins, and varnishes used to be made of hemp oil.
Hemp has long fibers which make its products stronger than if they were made of wood. Construction products like fiber board, oriented strand board, beams, studs, and posts can all be made from hemp.