The American farming landscape changed dramatically in the years from 1850 to 1950 due mostly to the introduction of farm tractors. Early tractors used steam engines and then the internal combustion engine was introduced in the twentieth century. The early steam engine tractor was primitive looking and gigantic and used chains on a rotating shaft to control steering.



Not long after tractors were introduced, farmers quickly found that engine driven tractors were more economical to use than keeping animals to till the land, so tractors began selling across the land. Many times agricultural machinery dealers would receive cattle as partial payment for tractors and they would in turn sell the cattle in the meat market. The Farmall is one of early tractors and the most familiar and famous names in tractor history. Tractors were made to be work horses, so niceties were minimal. This included foregoing a fuel gauge.

A tractor or tractors have been a must for farm owners as they are most useful for cultivation, but tractors are also used in construction, in excavation, and in manufacturing and industry. Farm size, availability of labor and custom services, crop selection, and cultural practices, such as choice of tillage system, all affect the selection of an optimum equipment set and, ultimately, the number of tractors necessary to farm. Although demand for tractor power generally increases with farm size, many commercial farms operate efficiently with a single tractor.

Tractors are designed to operate at different travel speeds, but the final drives are not necessarily designed for all torques theoretically available. Engine power, which typically ranges from about 12 to 120 horsepower or more and over the years have ranged between 20 and 400 horsepower, is transmitted through a gearbox usually having from 4 to10 speeds (these transmissions are manually controlled via a lever to determine how fast the tractor can go) to the differential gear which drives two large rear-drive wheels. Slow speeds are necessary to give the farmer more control while doing field work although some farm tractors can reach speeds up to 25 miles per hour.

Additional weight and ballast can be added to farm tractors for help in reducing wheel slip when pulling heavy loads. Insufficient ballast can cause increased fuel consumption and excessive wheel slip. Also, tractors use large tires to avoid compressing the earth and digging in. Only the rear tires really need to be large and unless the tractor has four wheel drive the front tires can be small and smooth. Tractors used on ground with irregular contours have front axels so mounted that their left and right front ends rise and fall independently of each other. However, soil contour can induce tractor and machine vibrations, which can reduce driver's comfort and his capability in controlling the linked machinery.

Tractors are usually used to pull, or in some cases, push objects and are designed to pull either large loads at slow speeds or lighter loads at higher speeds. Field speeds up to 10 mph are typical, but rangeland applications usually vary from 2 to 5 mph. Tractors can be generally classified as two-wheel drive, two-wheel drive with front wheel assist, four-wheel drive (often with articulated steering), or track tractors (with either two or four powered rubber tracks).

In order to prevent rollover the hitching point for tractors is below the rear axles. Some people, in an attempt to get more weight / traction, have unfortunately attached to a point above the rear axle of the drive wheels but this can lead to disaster. When a tractor is used to free and tow a stuck vehicle, the vehicles should be hitched front-to-front with a chain using the towing tractor in reverse. This method transmits all the engine power of the towing tractor through the chain to the towed vehicle thus minimizing the risk for rollover.

Most farm implements are attached to the rear of the tractor by either a drawbar or a three-point hitch. The three-point hitch, allowing the operator to lift the implement being towed and which transfers the weight and stress of an implement to the rear wheels of the tractor, was invented by Harry Ferguson in 1926 and has been standard since the 1960s.