Their is currently only a couple available sites to go on. The sites will be listed below for you to see and large map of these "sites".
The Isle is an large map and is the main map to play on. This is one of the largest maps currently in The Isle and includes many interesting geological features, such as canyons, mountains, bays, and other geological features. This map also holds most of the buildings left behind by the mysterious company of Apollo Engineering. It is also the main holding site of most of the dinosaurs you have saw within the "Dinosaur Catalog".
Isla Spiro is most know for its large spire, which is how it got its name. It is the new and improved version of The Isle map and has more interesting things to see. This map is currently still being worked on and expanded upon, however it should stay mostly the same until they expand out from that area, which is what the developers are planning to do.
Thenyaw Island is an much more enclosed map. It is surrounded by mountains on all sides and is mainly made up of forest, rivers, mountains, valleys, and large lakes. This island is much more suitable for dinosaurs who can't move fast considering how enclosed and compact the area is. Despite that, it still is an relatively large sized map.