This map is intended as one which will grow as more information comes to light, but is currently largely based on David Hearn’s 2013 article The Defences of the Mersey. It was published in volume 12 of the Liverpool History Journal, and is available to buy here: https://liverpoolhistorysociety.org.uk/liverpool-history-journal-13/
Most of the defences are gun batteries which trained their sights on the entrance to the River Mersey, where French ships were deemed a potential threat. I’ll leave it to David to explain the details of this defensive landscape, but suffice to say I thought it would be interesting to see on a map. Some of the information for the gun emplacements is from the article, backed up with further notes from the sources linked to in the pop-ups.