Where are custom maps saved?

I wonder where are saved the custom maps of the servers that we enter . I looked in the default folder "maps " but the map is downloaded not safe there .

 

If you downloaded from workshop.
Find the map on workshop. Subscribe. Go to, for me, c:\program files(x86)\steam\streamapps\workshop\content then there will be folders depending on how many workshop items you downloaded. On the page you subscribed to it says the map id. The first folders aren't the id. But look at the date installed. The next folder will be the map id. For me using Windows. I took the .win64.map and copied it into c:\program files(x86)\steam\streamapps\common\hurtworld\hurtworldclient_data\maps