The final 48,418ha (119,639 acres) of countryside has been opened up under the Countryside Rights of Way Act.
This marks the completion of the so-called right-to-roam across mapped areas of mountain, moorland, downland and registered common land in England.
The East (26,111ha) and the West (22,307ha) are the last areas to be mapped in England, bringing the total area of land under open access to almost three quarters of a million hectares of land.
Junior DEFRA minister Jim Knight said: “This is a very special day for everyone who loves our countryside, as it provides the opportunity for people to walk freely on access land, without the need to stick to paths, and to enjoy some of the most beautiful scenery that up until now has been off-limits.
“From today everybody can join in and celebrate the introduction of the right across the whole of England thanks to the hard work of many people and organisations.
“The Countryside and Rights of Way Act strikes a careful balance between the wishes of people to walk on access land and the needs of landowners and managers.
“However, along with this new right of access comes responsibility. I am encouraging walkers and visitors to follow the Countryside Code and signs, keep their dogs under control and find out about any restrictions on access which were in place.”