There are a number of different types of mills on The Land, which can be defined either by their power source or their purpose. Mill mechanisms include a wheel which turns an axle, which turns a series of gears, shafts, cams, stones, hammers, levers, or other parts. The first mills were invented by Maura in LY 152. Some different types of mills which are currently used on the Land include:
- Grist mills: For grinding grains into flour, or refining sugar. This replaced the use of mortar and pestle, starting around 152.
- Paper mills: For the production of paper, which is made from wood pulp (received from pulp mills) and/or cloth (received from textile mills). The method for producing paper was first devised in 170. It soon replaced parchment for writing on, but various other uses for different varieties of paper were soon found (which led to an increase in the production of trash, as some uses for paper replaced items which would be washed after use rather than disposing of them).
- Powder mills: For the production of huo yao. The first of these was built in Ship in 365, by the Coast Guard. For centuries, only the Coast Guard were allowed by any village to produce huo yao, but such mills were constructed in secret in the Northern Alliance in 901.
- Pulp mills: For preparing wood chips or other plant fibres, using a thermomechanical pulping method. Once the pulp has been prepared, it is sent to paper mills (which are usually very near the pulp mills). First used in 170.
- Saw mills: For sawing logs into finished lumber. Saw mills also send wood chips to pulp mills (which are usually very near the saw mills). First used in 163.
- Textile mills: For the conversion of fibres such as rainbow qutn, hemp, flax, or wool into yarn, thread, candle wicks, or rope. (Some of these materials were first prepared in threshing mills.) Other machines in the textile mills would be used to weave or knit yarn or thread into various types of cloth. Textile mills first came into use in 162, replacing methods of textile production which had been in use since the time of Connor and Brigid. Textiles are used for many purposes, such as making clothing, curtains, bed sheets, tents, coin purses and other bags, canvases for wagons, sails for ships, etc. However, some early uses for textiles have largely been replaced by paper products. Some cloth might also be sent to paper mills.
- Threshing mills: For separating chaff from cereal grains such as barley, corn, rice, and wheat. This replaced the use of flails, starting around 152. Some threshing mills also were used to prepare plant fibres such as flax and qutn, before sending them to textile mills.
- Strider mills: This is the first type of mill to be designed by Maura. Striders would be harnessed to a horizontal gear wheel, walking in a circle to turn the wheel, which powered a system of gears and other devices. Striders, and later oxen (staring around 225) were used to power both threshing and grist mills.
- Water mills: The second type of mill to be designed, also by Maura, in 162. Water mills largely replaced striders as the primary source of power for mills, though strider or oxen-powered mills have never fully disappeared from the Land. The earliest water mills used undershot water wheels, built on First River, though some time later aqueducts, which previously had been used for irrigation of crops, were redesigned to be used in conjunction with overshot water wheels. Water mills are different from strider mills in that the main water wheel is vertical rather than horizontal, and the mechanisms it drives are often more complex. Like strider mills, water mills can be used for threshing or grinding, but they have also been adapted over the years for a number of other purposes. Since 888, water mills have also been used to power piston pumps.