Parts of Pontefract Castle not seen by the public since the 17th century will be opened up as part of a £3.5m project at the site.
A £3.045m grant from the Heritage Lottery Fund (HLF) along with another £455,000 from Wakefield Council and English Heritage will also allow a new shop and cafe to be built at the castle, along with a restoration of the arts and crafts barn.
The castle’s Sally Port, Swillington Tower, which have not been seen by the public since 1649, will be opened up as part of the restoration works.
Council leader Peter Box said: “We are delighted that the HLF is supporting our work at Pontefract Castle with this grant.
“The money will help put Pontefract on the map for tourists, building on what is an already popular site, and will certainly bring wider economic benefits to the town.
“I’m sure people from all over the district and beyond will be keen to join in with one of the events made possible by this extra money and experience a piece of thousand-year-old history.”
The grant will also allow a range of education activities to be held at the castle and there will be volunteering opportunities.
Coun Les Shaw, cabinet member for culture, leisure and sport, said: “Pontefract Castle is significant not just in our district’s history, but in the country’s history.
“It was the site of the death of King Richard II and a Royalist stronghold during the English Civil Wars.
“How amazing to think that we can open up parts of this immensely important building not seen for hundreds of years.”