When it comes to defining the word "most mapped," several synonyms come to mind. Firstly, you could use the term extensively surveyed, meaning an area or territory that has been thoroughly studied and researched. Secondly, you could say frequently charted, which denotes that a location has been repeatedly plotted or recorded from different angles. Another option is heavily documented, indicating that there is a great deal of information available about a particular space, such as historical or geographical data. Lastly, densely plotted could be another way of expressing the idea that a location has been extensively mapped, examined, or recorded. Whichever term you choose, it's essential to consider the context in which it will be used to find the best synonym.