An inground flagpole is simply a flagpole that is rooted in the ground. It is a permanent pole designed to withstand winds of up to 130 mph, depending on the height and material of the flagpole. Just as trees require roots for support, inground flagpoles need foundations.

A foundation is made by digging a hole, wetting the soil, and pouring in concrete. A cylindrical groundsleeve is then inserted into the wet concrete. A groundsleeve is a thick steel cylinder with an open top and a wide base, designed to protect the flagpole from the corrosive effects of the concrete. On the outside of the groundsleeve are steel plates that lock it in place. On the inside of the groundsleeve are steel wedges that firmly center the base of the flagpole. Oftentimes the groundsleeve will include a ground spike to channel away lightning (but this might be of little concern if you have a fiberglass flagpole, the only flagpole material that does not conduct electricity.)

The foundation may also include a flash collar, which fits over the ground sleeve and bottom of the pole to protect it from the elements and give the foundation a finished look. Space between the collar and pole is sealed to keep water away from the base of the pole and the foundation.

When building your foundation, it is important that the flagpole extends far enough underground so that it will not blow over. A good rule of thumb is that ten percent of the poles length should be underground.

Some of the larger flagpoles do require professional installation. Ask the manufacturer or distributor whether they will do it for free with purchase.