From Sunday new powers come into force in south-east and "lower north-west" England allowing ramblers greater access to 105,253 hectares of land.
Ramblers have been fighting for decades for better access
BBC News Online looks at why the new rights came about.
Q: What is the right to roam?
On 19 September, new rights laid down in the Countryside and Rights of Way Act 2000 start coming into force in Kent, Sussex, Surrey and Hampshire, as well as the Forest of Bowland, Lancashire, and the Peak District.
They grant walkers access to open country and registered common land in England and Wales and will be rolled out across both countries in the next 15 months.
New maps are being published over the next year, showing where ramblers can walk over areas of privately-owned moor, mountain and heath land.
Q: How long has the act been in the pipeline?
The fight to open up large areas of countryside to the public goes back decades.
The first attempt to create a legal right to roam came with the MP James Bryce's 1884 bill for free access to Scotland's mountains.
It failed - as have 10 other attempts to introduce a freedom to roam bill in the 120 years since then.
Violent clashes between walkers and gamekeepers on Kinder Scout hill, in Derbyshire, in 1932 pushed the issue further into the public eye.
Q: Why do we need the act?
The Ramblers' Association says the new legislation will mean everyone, whether rich or poor, will be able to enjoy the wild landscapes of England and Wales.
Supporters say a centuries-old tradition of free access has been eroded in the last few decades as private ownership has changed.
While the Forestry Commission has always allowed access to its property, the sale of much of its land has closed thousands of acres to the public.
Q:Why is it controversial?
While some say people have the right of access to countryside that has often been open for generations, others say landowners have the right to protect their own property.
Some landowners see it as a dangerous free-for-all which would damage the economic and environmental viability of their land.
For example, some farmers are worried walkers will not keep dogs on leads and allow them to foul their fields.
Some landowners have complained that some areas have been wrongly included on maps drawn up to show ramblers where they have a right to roam.
And there are some concerns that the new laws will invade their privacy.
In June, pop star Madonna won a bid to keep ramblers from part of her estate on the Wiltshire/Dorset border saying her human rights would be infringed.
Q: What governs ramblers' behaviour?
The Countryside Agency has drawn up a Countryside Code, asking walkers to "respect, protect and enjoy" their surroundings.
It expands on long-standing reminders to walkers to close farm gates, keep dogs under control and protect animals and plants.
And it urges walkers to plan ahead and follow local advice on whether areas may be restricted due to breeding seasons or while work is carried out.
However there is no legal obligation on walkers to follow the code.
Q: How will the act be enforced?
The new right of access will be managed by local authorities and national park authorities.
Magistrates will also be able to use greater powers to clear blocked paths and there will be tougher penalties for wildlife offences.