The area is known to have been occupied during the Iron Age and by the Romans. It was during these periods that there was the first significant human impact on the landscape, through major woodland clearance and replacement with arable and pastoral land.

From the beginning of the 5th century the Saxons settled in the area and there followed a major regeneration of woodland. This was largely due to the majority of the population retracting from the boulder clay plateau and becoming concentrated in the river valleys where the geology had better agricultural potential.  By the 8th century there had again been a significant expansion of arable land although most of this was probably converted from pasture rather than woodland. The first core areas of the open field system were established at this time and were an integral part of the Saxon townships that developed from the earlier provinces and multiple estates. The open field system would continue to expand and dominate the landscape in future centuries. There were, however, still large areas of land and forest that were not allocated to the townships and these were owned by major royal or former royal manors.

Following the Norman Conquest much of the manor land was taken into forest law to create a royal hunting forest for William the Conqueror. Under forest law it was an offence for anyone to hunt within the forest boundaries other than the king. This included the landowners, although they could make a payment and be granted a ‘warren’ which would enable them to hunt fox, hare and fowl only. The King also took all rights to grazing, minerals and timber on the land.
Deer

The term ‘Forest’ represented an area of legal jurisdiction relating to the king’s hunting preserves rather than an area of continuous woodland. By 1157 the forest had taken its name from the royal castle of Rockingham although it was subdivided into three administrative areas known as bailiwicks. Consequently, the forest was managed from the royal manors of Rockingham, Brigstock and Kings Cliffe.

Officials periodically carried out a ‘perambulation’ of the Forest which established its boundaries and therefore the land that came under forest law. These boundaries were subject to substantial change and during the late 11th and 12th centuries, additional woodlands and townships (with their open fields) were progressively included in the forest area. Following the perambulation of 1286 the Forest covered an area of 350 square miles and stretched from the southern edge of Stamford to the walls of Northampton.  This was followed by a substantial reduction of the royal forest when, in return for supporting Edward I and his army, the manorial lords were granted ‘disafforestation’-exemption from forest law for their lands. The perambulation of 1299 redefined the Forest as covering only 77 square miles, these boundaries were to remain in place for over 300 years.

In the 14th century the expansion of the previous centuries came to a sudden halt under the impact of famines and plagues and the population of the Forest plummeted. The 15th century saw further major changes in landuse as, partly due to the drop in population, the production of wool became more profitable than production of grain. With the large scale conversion of arable to pasture came the first enclosures of the open field system to create huge hedged fields and sheep walks. The 16th century saw the enclosure process continue across the Forest. This seems to have mostly been whole townships being enclosed by agreement although there was a degree of coercion by landowners and some tenants being forcibly ejected. The enclosure process was to continue to gradually change the landscape of the Forest for the next 300 years. 

Charles I saw the Forest as an opportunity to raise funds for the royal coffers and, as well as selling off further tracts of woodland, he resorted to rigorous enforcement of the forest law and fines. In 1639 Charles extended the Forest boundaries far beyond those set in 1299. This action was intended to force the major landowners into paying for disafforestation but following intense protests the king gave up his attempt to maintain forest law. A final perambulation was made in 1641 and this time the boundaries reverted to being even smaller than the 1299 levels as a result of newly disafforested land.

The years of the Civil War and the Restoration saw little interest taken in the Forest and Charles II sold and gave away further areas of woodland. This process continued until by the end of the 18th century there was only a small amount of woodland still in royal ownership. An official report of 1792 found that, compared to the private woodlands, the remaining Forest was in a very poor condition resulting from a lack of management and centuries of constraint.
The final stages of the dissolution of the Forest took place with parliamentary enclosure of the bailiwicks, culminating in the official disafforestation of Rockingham bailiwick in 1832. This was followed by further land sales and substantial woodland clearance for agriculture. The last remnants of the Forest were placed in the hands of a Commissioner for Woods and Forests and finally into the care of the newly formed Forestry Commission in 1923. 

During the remainder of the 20th century the Commission carried out further clearance and replanting, mainly with Norway Spruce. When the Spruce suffered large scale die-back in the 1980s and 1990s Forest Enterprise carried out a policy review and decided to concentrate on the restoration of native woodland. The Ancient Woodland Project was launched in March 2000 and involves the removal of conifer plantations and the restoration of semi-natural woodland with species such as Ash, Oak and Field Maple.