Historic England has confirmed that part of a field at Uffington will become a 'Scheduled Monument', owing to its archaeological importance.
The designation comes despite the farmland being included in Shropshire Council's Local Plan for potential development as an employment site.
Shropshire Council has confirmed it has been notified of the scheduling but said no decision had been taken on whether it would continue with its inclusion in the local plan.
Eddie West, Shropshire Council’s planning policy and strategy manager, said the issue would be discussed by planning inspectors at further hearings over the local plan next spring.
Historic England says there is an expectation that scheduled monuments "will be handed on to future generations in much the same state that we have found them".
A report from Historic England shows that the land owner, and Shropshire Council both argued against the site becoming a scheduled monument.
The council said that farming on the land was likely to have degraded any below-ground features of the camp, and that the land being bisected by the A49, along with overhead power lines compromise its integrity.
The report shows the landowner argued that "the degree of survival of the camp does not justify scheduling", adding that there are "more appropriate mechanisms to preserve its interest".
Historic England says the camp is the fourth largest known if its kind in England, and adds that it is one of 18 sites, either in, or close to Wroxeter.
The evidence shows it initially covered 16 hectares, but was later expanded by another two hectares, possibly when it was re-used.
Historic England's listing on the land states: "Although common in Scotland, Roman temporary camps larger than 15 hectares are very rare in England, accounting for less than 10 percent of those camps well preserved enough to deduce their area.
"At 18 hectares for its larger phase, Uffington is amongst the very largest English camps.
"As Roman camps were constructed very quickly to be defensible positions, it was expedient to build no larger than necessary and utilise the full extent of the interior.
"Therefore, Uffington’s size suggests that it could have been used by a force in the region of two full legions, or just over 10,000 soldiers."
Historic England says the site was surveyed last year, but that there were no Roman finds made during the work.
Its report states: "A geophysical survey was carried out in August 2021, the results of which corroborated the features identified from aerial photographs and informed the location of six evaluation trenches excavated in September 2021.
"These 2021 trenches revealed the northern and southern perimeter ‘V’ profile ditches of the camp as well as confirming an entrance in its long north side.
"No Roman finds were recovered during this or the earlier excavation, though given the small area excavated and brief occupation of camps by soldiers carrying material goods limited to the necessities of campaigning, this is not unexpected."
Historic England also suggests the camp could have been a base for an invasion force, stating: "The size and location of the Uffington camp indicate that it was a staging post for an army marching en-route to Wales.
"Supporting this interpretation, Uffington has been linked with a series of camps running in a route north-west from Wroxeter via Whittington near Oswestry in Shropshire, then on to Pen Plaenau and Penrhos in Wales.
"All four camps are of similar distinctively large size (between 15 and 18 hectares) and could have accommodated a similar number of soldiers.
"Use as a marching camp could have occurred during the initial Claudian invasion from the late-40s AD, the second wave of activity under Nero in the late-50s (coinciding with the move from fort to fortress at Wroxeter), or the campaigns of Agricola in the later-1st century AD."
Mr West confirmed the council's position on the decision, saying: “Following several months of consideration, and the submission of the draft Shropshire Local Plan for Examination in September 2021, Historic England have concluded that land at Uffington, Shrewsbury should be included on the national Scheduled Monuments list.
“This land is currently proposed as part of a strategic employment allocation in the emerging Local Plan. The Local Plan is currently subject to Examination in Public and the Inspectors appointed to examine the Plan have been informed of the situation.
“The council accepts the decision of Historic England on this matter, but as yet have not taken any decisions on the implications for the future allocation of this site.
“It is anticipated this issue will be discussed further at the future stages of the Examination, anticipated to happen in Spring 2023.”