Last name ברנן (Brennan 
, ברנן 
) , all around the world, is a common surname. The cognomen ברנן is characteristic of Northern Europe, particularly Ireland, where it is a common surname, Guernsey, where it is quite a common surname, and Jersey (explore the name in all countries). Not in comparison with a country's population, it is the most numerous in the United States, Ireland, and the United Kingdom. Very seldom, ברנן is the forename as well as the last name.