Prison facts

Alcatraz Prison Facts and Numbers

The statistics that explain how the penitentiary actually worked.

Strip away the film mythology and Alcatraz becomes a set of numbers: cell dimensions, count frequencies, staffing ratios and shipping costs.

Key numbers

Operating years1934–1963
Main cells336
Cell sizeAbout 5 ft × 9 ft
Typical population260–275
Total inmatesAbout 1,545
Guard-to-inmate ratioRoughly 1 to 3
Daily countsA dozen or more
Escape attempts14, involving 36 men

Rules and privileges

Inmates were guaranteed food, clothing, shelter and medical care. Work, visits, the library and yard time were privileges to be earned — and lost. The early silence rule was among the most resented policies and was eventually relaxed.

Costs

Everything arrived by boat, including fresh water. That logistics burden, plus salt-air corrosion, is what eventually closed the prison — see why Alcatraz closed.

Myths worth correcting

  • The Birdman kept no birds on Alcatraz.
  • Sharks in the Bay are not man-eating species; cold and current were the real barriers.
  • Inmates were not sentenced to Alcatraz directly; they were transferred there.
  • The food was, by design, among the best in the federal system.

Frequently asked questions

How cold is the water around Alcatraz?

Typically around 50–55°F year-round, cold enough to cause rapid hypothermia.

Were there sharks around Alcatraz?

The Bay has sharks, but not species that threaten swimmers. Cold water and strong currents were the real obstacles.