The State's first nature reserve, the Glen o' the Downs in Co Wicklow, is to reopen before Christmas, the National Parks and Wildlife (NPW) service has announced.
Access to the Glen o' the Downs was closed in the summer of 2000 when signs erected at the N11 car park proclaimed "Closed till end August".
The signs did not specify which August. A spokeswoman for the parks and wildlife section of the Department of the Environment said the car park and public paths in the reserve, which have become overgrown by grass and brambles, are to be cleared.
The car park was home to an anti-roads protest over three years, to 2000, when self-styled "eco-warriors" lost their case against the building of a dual carriageway through the glen, and were subsequently removed by gardaí.
An earlier nature trail which preceded the Wicklow Way in the nature reserve has fallen into decay.
Picnic tables and seats, wooden bridges across a stream, and leaflet information boxes are all in a state of disrepair.
Wooden steps have collapsed, while grass areas have become overgrown by brambles.
Point marks and signs which were part of the marked way have also decayed, and most are no longer visible. The stream is littered with refuse and road signs from the adjacent road works.
According to a spokeswoman for the Department, Wicklow County Council is to carry out the works to the car park while the parks and wildlife service will clear away the paths in the reserve.
The nature trail, which has been in decay for many years, will not be renewed.
The spokeswoman said the work would "likely" begin in the coming weeks and would take one or two weeks to complete.
The nature reserve should be accessible from the N11 by Christmas, she said.