Paper mills are factories dedicated only for the production of paper and paper-related products. They inherited their name from the wood mills, who were in early 19th century slowly transformed into manufacturing facilities for processing wood into form that is suitable for the production of wood pulp.
First mills had little machinery, and were powered either by manpower, animal power or water power (first mentioned in late 13th century Spain). That power was routed to the machines or tools that pounded wood chips into pulp that was ready to be pressed into sheet-shaped molds to create individual papers.
With more and more mills being situated near water that powered its machinery, those mills became perfect candidates to be transformed in either fully integrated or nonintegrated paper mills with the arrival of revolutionary Fourdrinier machines in the first years of 19th century. Nonintegrated mill was the one that had only prepared wood for the final processing that happened offsite. Integrated mill had both of those facilities on a single site, enabling easy paper production upon receiving of wood logs of chips.
First paper mills equipped with the Fourdrinier machines were established in Frogmore, Hertfordshire in 1803. From that point on paper mills started springing all across England, continental Europe and New England in the United States, slowly spreading to the rest of the world. Newly found ability to create vast quantities of paper revolutionized paper industry, that has for centuries and millennia (excluding China and Arab countries) been limited by the production of the quality paper made from animal skins (parchment or vellum) and in much lesser degree by papyrus that was rarely used in Europe.
Early 20th century saw the establishment of paper mills who dramatically reduced forested areas in Europe and United States, most famously New Hampshire mills owned by Brown Company. Only during 1907, this company managed to cut down between 30 to 40 million acres of woodlands on their property, managing to promote foundation of mills that were powered by the logs that were cut down and driven across rives to the gathering sites near mills. Those types of mills have largely become a thing of the past now in early 21st century.