As you can see, there are 42 hillforts listed in the Somerset HER database (minus a couple of perhapses). There are of course many more than this in the whole Somerset area, but not all boroughs have made their information available online. Still, 42 is an excellent number, and more than enough to be going on with for the moment. Have a browse through the links below - each will take you to an individual page which will display a close up satellite image of the hillfort in question, and also the relevent HER data for that monument. The maps are downloadable as a .kmz file from each page.
At the bottom of each page is a list of recommended books on the subject of Iron Age fortifications - these have been hand picked for usefulness to the general reader - the list is not auto-generated. The links will take you to the Amazon page for that book, and if you make a purchase you will be helping to support Digital Digging. Thanks in advance, should you decide to go down that route.