An example of end gateway generation shown on a graph in X-Z coordinates. Blue dots represent the main island gateways, red dots represent the outer islands gateways. The lines display which gateways connect to each other.
A new end gateway portal generates near the edge of the main island each time the ender dragon is defeated. A maximum of twenty portals can be generated for each world, arranged in a circular fashion around the island at Y-level 75, approximately 70 to 100 blocks away from the center (0,0). Killing the ender dragon afterwards will not generate further portals.
An additional end gateway portal will generate in the outer End regions after activating one at the main island. These gateways generate at Y-level 66 to 69. If there are no blocks within a five-block radius from the gateway below these. Y-coordinates however, then it generates above the usual level until there is a block below the structure within the radius. The exact X-Z position where the gateway generates in the outer islands is random, but it is always within ~1000 blocks from the center and relative to the X-Z coordinates of the first gateway portal and (0,0).