Sherwood Forest's national nature reserve has nearly doubled in size after taking in a section of heathland.
The nature reserve now looks more like the old Sherwood Forest
Budby South Forest has become an official part of Sherwood, increasing it from 220 to 423 hectares (494 to 1,044 acres).
Natural England, a newly-formed organisation which improves the natural environment, said important heathland would be better protected.
Budby South Forest is Nottinghamshire's largest area of dry lowland heath.
Situated between Edwinstowe and Worksop, it is home to nightjars and woodlarks whose population is increasing.
Stephen Clifton, from Natural England, said: "We now have a natural nature reserve that is truly characteristic of the old Sherwood Forest, with areas of old woodland and ancient oak trees.
"We've got a fantastic site for both wildlife and people."