[laynee]

Find married name of long-dead female relative. Know date of birth and state.

[JudyKayTee]

find married name of long-dead female relative. Know date of birth and state.

Without the information you have this is impossible.

Hire an investigator and provide all the info you have.

[Fr_Chuck]

Have you joined and paid membership on sites like Ancestory.com I found info on family going back 4 and 5 generations, married names, copies of birth certificates and more