Highland Council has said that it will submit a planning application for a viewing platform and shops for part of Inverness Castle before Christmas.
The local authority owns the North Tower and is leading a study into how it could be made available to tourists.
Built in stages in the 1800s on the site of previous historic castles, the sprawling Inverness Castle was first used as a county hall and later a jail.
In more recent times it has served as Inverness Sheriff Court.
But because the tower is owned by the local authority it could be opened up to visitors sooner than other parts of the site.
The viewing platform, which would give views of Inverness and the surrounding landscape, could be opened to the public next year or early 2016.
Highland Council joined the Scottish government in setting up a working group earlier this year in a broader project looking at the castle's future tourism potential.