As far as I know these are California, Pennsylvania, and Texas.
But remember it's not the in-patient externship that program directors are looking for. They just want to know that you are safe with patients and have familiarized yourself with how things are going on in USA.
Moreover, in clinic setting you usually get stronger LORs with words like outstanding, excellent while in hospital settings you get words like met the requirements and attended.
Generally speaking outpatient externships are the only real hands-on externships that you can get.