Overseas - the word when used as a noun like describing the residence or location does not need 'in' for the preposition - if I remember correctly.
"I live in overseas" - incorrect, isn't it? I am troubled with this right now during inhouse paper review (non native reviewing) and actually this sentence is closer: 'reports were published in overseas and the U.S.'. I would choose another way to say this as it appears somehow wrong.
I had a source to check the correct usage but isn't in the immediate place, so I would appreciate somebody giving me an assurance for my obsecure memory.