Brighton and Hove Albion's planned stadium at Falmer has escaped being included within the borders of the proposed South Downs national park.
The Countryside Agency today published a designation order for the park, with boundaries stretching across East and West Sussex to Hampshire.
People are being given their last chance to have a say on the likely size and shape ahead of a public inquiry.
The agency will now recommend the Government sets up a national park authority to look after the South Downs.
Members of the public have four weeks to express their views before the government decides whether or not to approve the designation order.
The Department for the Environment, Food and Rural Affairs is likely to call a public inquiry because objections are expected from local authorities.
A new stadium at Falmer would fall outside the park's borders, although a proposed transport interchange at Village Way North would be inside them.
Chris Todd, campaigns officer for the South Downs Campaign, said: "We want to warn people not to be complacent - just because their area has been included does not mean it cannot be excluded later on.
"It is essential for people to express support both for the principle of the national park and for their local area."
Only people who make representations to Defra before the February 28 deadline will be eligible to take part in a public inquiry.
Brighton and Hove City Council has backed the national park but East Sussex County Council is calling for a public inquiry.
County council leader Peter Jones said the national park designation was "unnecessary".
He said: "The existing arrangement, and the work done by the South Downs Conservation Board, is wholly adequate.
"This would be replaced by an undemocratic structure imposed by the secretary of state, and made up of people who may or may not have anything to do with the area."
View the boundary map at: www.countryside.gov.uk/proposednationalparks/sd_desigIntro.asp
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