How do you find out if a person is in jail?

if you know their last name look online for your states department of corrections.Put there last name in.

Another View: The above will probably work if the person is in prison.

However, if the the person is in JAIL, you would have to call the jail itself or the arresting agency to inquire about this infomration over the phone.

There is such a large and constant turnover of inmates in jails that it is impractical and too costly to keep constantly changing and updating computer data.