"Antique iron" is a broad term encompassing anything from the smoothing stones used in the European Viking Age to the "vintage" electric irons that came into vogue in the 1900s. Today, an antique iron is most often defined as being made of cast iron. It is heated over an open flame or with coals before pressing clothes.

The tradition of forging irons to press clothes dates back to the Middle Ages, and variations on the practice were found in many countries. For instance, in China, flat-bottomed iron pans were filled with hot coals and then used to smooth out wrinkles in clothing. Other irons were shaped from soapstone or terra cotta, materials which could be reheated over and over again without melting.

Antique irons were originally used in pairs. One would be used while the other heated up, and vice versa. The variable heat from the fire made ironing a delicate process requiring skillful judgment to avoid scorching the cloth. The irons would need to be cleaned and smoothed often with sand in order to make sure they didn't leave any marks on the clothing. A fine layer of beeswax would be applied to keep clothes from sticking. Much like a cast-iron pan, the irons would also have to be oiled in between uses to prevent rust.

The form of the antique iron has evolved over time. Many small details changed in order to make ironing an easier task, even while the basic procedure remained labor-intensive. One area subject to change was the iron's handle, which when made of the same piece of metal as the iron's base, would become too hot to handle without using a pad or a rag. In response to this, removable handles that could remain cool while the rest of the iron heated up were invented. The handle could then could be replaced for pressing.

Another form of antique iron is the box iron, also called a charcoal iron. They were more technologically advanced in that they contained a hollow space inside for coals. Pieces of metal, called "slabs", could be inserted after heating as well. Hot bricks could also be placed inside an antique iron to achieve a gentler and more uniform heat suitable for delicate fabrics.

Antique irons are collectible. People enjoy owning a piece of history as well as puzzling out the names of their original manufacturers. Many irons were marked with symbols when they were produced to identify what company they came from. These symbols do not usually incorporate names and can be cryptic without the use of handbooks or other materials dedicated to identifying them.