Exmoor National Park Authority says it may have to make 'painful cuts' due to a gap in funding.
The national park gets £1million less in grant funding than it did in 2010 and needs to make a further £500,000 worth of cuts in the next three years.
Bosses say they are considering urgent money-saving measures like selling off land, closing visitor centres and making redundancies.
Exmoor National Park's chief executive Sarah Bryan said: "These are really difficult times for us.
"We manage a beautiful landscape working with farmers and the local community, but the authority now risks having to close up to two of our three visitor centres, make redundancies right through the organisation and no longer being able to manage 1,000km of paths.
"I've worked in national parks for nearly 30 years, and I've never seen it anywhere near as bad as this.
"The authority could also be forced to sell land that belongs to the nation such as woodland and moorland and to increase charges in certain areas.
"This would be a huge disadvantage to people on low incomes who have found landscapes like this invaluable, particularly in the past few years during Covid.
"The average cost to visitors per year is relatively very little, but the benefits to physical and mental wellbeing are priceless," she added.