How many stories high is Alcatraz?

Answer 1

The island is around 130 feet, so about 13 stories.

The prison building itself is on a slope, and the main prison area is a large, warehouse-like building, so this is a bit tricky to answer.

In the main area of the prison, the cellblocks are three tiers high, with an empty tier above them. On the northeastern part of the building, there are three floors: the hospital wing on the top floor, the dining hall on the main floor, and the basement on the bottom floor (though it's not really a basement, as it has full depth walls and windows.)