What body of water surrounds Belfast and Rockall?

Question

Update:

I meant what body of water is Belfast and Rockall on? 

Answer 1

Belfast is on the North Channel.

https://en.wikipedia.org/wiki/North_Channel_(Great...

if you what to be more specific Belfast is on an inlet called Belfast Lough.

https://en.wikipedia.org/wiki/Belfast_Lough

Rockall is in the North Atlantic Ocean.

Answer 2

Rockall is in the North Atlantic Ocean. Belfast isn't surrounded by a body of water.

Answer 3

The Irish Sea.