Vikings contribute directly to the expansion of your Berk. Vikings are required to construct and/or upgrade certain buildings during the course of the game as well as removing rocks. Essentially, for your Berk to grow and expand, your total Viking population must increase. To increase your number of Vikings, you must build and/or upgrade Viking buildings. You can read more about Viking buildings here.

 

The Meade Hall is the central activity point in any Viking village. Your Meade Hall level will determine your current Viking limit. Once this limit is reached, you will need to level up your Meade Hall to allow for additional buildings/upgrades to be built for Vikings to move in.

 

Once you reach Meade Hall Level 12, the Great Forge will allow you to upgrade your Viking buildings to get more Vikings on your island.

 

Taking all of the above, this can be summed down in the following way: To increase your number of Vikings, you must build/upgrade Viking buildings. To get more Viking buildings you must upgrade the Meade Hall.