The concept of "crop circles" began with the original late-1970s hoaxes by Doug Bower and Dave Chorley (see
Bower and Chorley, below).
 They said that they were inspired by the
Tully "saucer nest" case in Australia, where a farmer claimed to first have seen a UFO, then found a flattened circle of swamp reeds.
Prior to the 20th century
A 1678 news pamphlet
The Mowing-Devil: or, Strange News Out of Hartfordshire is claimed by some cereologists to be the first depiction of a crop circle.
 Crop circle researcher Jim Schnabel does not consider it to be a historical precedent because it describes the stalks as being cut rather than bent.
 (see folklore section)
In 1686, British
Robert Plot reported on rings or arcs of mushrooms (see
fairy rings) in The Natural History of Stafford-Shire and proposed air flows from the sky as a cause.
 In 1991 meteorologist Terence Meaden linked this report with modern crop circles, a claim that has been compared with those made by
Erich von Däniken.
An 1880 letter to the editor of
Nature by amateur scientist
John Rand Capron describes how a recent storm had created several circles of flattened crops in a field.
In 1932, archaeologist E C Curwen observed four dark rings in a field at Stoughton Down near Chichester, but could examine only one: "a circle in which the barley was 'lodged' or beaten down, while the interior area was very slightly mounded up."
In 1963 amateur astronomer
Patrick Moore described a crater in a potato field in Wiltshire, which he considered was probably caused by an unknown meteoric body. In nearby wheat fields, there were several circular and elliptical areas where the wheat had been flattened. There was evidence of "spiral flattening". He thought they could be caused by air currents from the impact, since they led towards the crater.
Hugh Ernest Butler observed similar craters and said they were likely caused by lightning strikes.
In the 1960s, in
Tully, Queensland, Australia, and in Canada, there were many reports of UFO sightings and circular formations in swamp reeds and sugar cane fields.
 For example, on 8 August 1967, three circles were found in a field in
Duhamel, Alberta, Canada, and the
Department of National Defence sent two investigators, who concluded that it was artificially made but couldn't make definite conclusions on who made them or how.
 The most famous case is the 1966 Tully "saucer nest", when a farmer said he witnessed a saucer-shaped craft rise 30 or 40 feet (12 m) up from a swamp and then fly away. When he went to investigate the location where he thought the saucer had landed, he found a nearly circular area 32 feet long by 25 feet wide where the grass was flattened in clockwise curves to water level within the circle, and the reeds had been uprooted from the mud.
 The local police officer, the
Royal Australian Air Force, and the
University of Queensland concluded that it was most probably caused by natural causes, like a down draught, a
willy-willy (dust devil), or a
waterspout. In 1973, G.J. Odgers, Director of Public Relations, Department of Defence (Air Office), wrote to a journalist that the "saucer" was probably debris lifted by the causing willy-willy. Hoaxers Bower and Chorley said they were inspired by this case to start making the modern crop circles that appear today.
Since the 1960s, there had been a surge of UFOlogists in
Wiltshire, and there were rumours of "saucer nests" appearing in the area, but they were never photographed.
 There are other pre-1970s reports of circular formations, especially in Australia and Canada, but they were always simple circles, which could have been caused by whirlwinds.
Fortean Times David Wood reported that in 1940 he had already made crop circles near
Gloucestershire using ropes.
 In 1997, the Oxford English Dictionary recorded the earliest usage of the term "crop circles" in a 1988 issue of
Journal of Meteorology, referring to a BBC film.
 The coining of the term "crop circle" is attributed to
Colin Andrews in the late 1970s or early 1980s.
The majority of reports of crop circles have appeared in and spread since the late 1970s
 as many circles began appearing throughout the English countryside. This phenomenon became widely known in the late 1980s, after the
media started to report crop circles in
Wiltshire. After Bower's and Chorley's 1991 statement that they were responsible for many of them, circles started appearing all over the world.
 To date, approximately 10,000 crop circles have been reported internationally, from locations such as the former
Soviet Union, the
Canada. Sceptics note a correlation between crop circles, recent media coverage, and the absence of fencing and/or anti-trespassing legislation.
Although farmers expressed concern at the damage caused to their crops, local response to the appearance of crop circles was often enthusiastic, with locals taking advantage of the increase of tourism and visits from scientists, crop circle researchers, and individuals seeking spiritual experiences.
 The market for crop-circle interest consequently generated bus or helicopter tours of circle sites, walking tours, T-shirts, and book sales.
Since the start of the 21st century, crop formations have increased in size and complexity, with some featuring as many as 2,000 different shapes
 and some incorporating complex mathematical and scientific characteristics.
The researcher Jeremy Northcote found that crop circles in the UK in 2002 were not spread randomly across the landscape. They tended to appear near roads, areas of medium-to-dense population, and cultural heritage monuments such as
Avebury. He found that they always appeared in areas that were easy to access. This suggests strongly that these crop circles were more likely to be caused by intentional human action than by paranormal activity. Another strong indication of that theory was that inhabitants of the zone with the most circles had a historical tendency for making large-scale formations, including stone circles such as Stonehenge, burial mounds such as
Silbury Hill, long barrows such as
West Kennet Long Barrow, and
White horses in chalk hills.