Helen Morgan, Liberal Democrat MP for North Shropshire, made the comments after meeting campaigners from Hands off Old Oswestry Hillfort (HOOOH), the group seeking to protect the ancient site.
The Iron Age hill is one of the best preserved in the country, but it has been the subject of an ongoing battle against housing projects on the land around the historic settlement.
The latest application for 83 homes on land off Whittington Road was turned down in March – but not due to concerns about the impact on the fort.
Planning officers instead chose to refuse Galliers Homes’ proposal due to its effect on local roads, drainage and the environment.
Today Ms Morgan, who was elected in a surprise by-election in December, spoke of the need to protect the historic landmark – and make the most of the opportunities it offers, both for locals and for tourists.
She said: “It’s such an important monument and part of our heritage, we should try to preserve its separation from the city so that people can properly appreciate it.
“It is a site of national importance, which is why there have been such prestigious supporters.
“We have a duty to preserve it for future generations to understand and appreciate our history. It’s something we should be proud of and try to take care of.”
During a visit to the site, Ms Morgan was guided by an expert archaeologist.
Ms Morgan said the opportunity was there for the town of Oswestry and the wider region to attract more visitors to the county.
“With the opening of the Cambrian Railway – it’s a real win for the town – it’s a local tourist attraction,” she said.
“The fort is another important part of the city’s history and if we want people to visit and spend their money here, we have to take care of these sites.”
Ms Morgan said those wishing to protect the hill could push further for an ‘exclusion zone’ for planning around the historic site.
She said: “I think the campaign team would like to see some sort of exclusion zone around it for development so that people don’t submit planning applications for this place.
“It is feared that once you allow development in this space there will be ‘infill’ in the rest of the green space between the fort and the road.”