Walter McNamara 1885-1920

I am trying to trace my Grandfather`s Birth Certificate. Walter McNamara born in 1885 in the USA. I have his marriage and death certificates.
can some one advise me how I can contact the US authorities particulary the Mormom`s in Salt Lake City I do not know what State he was born
His Parents were Timothy McNamara and Mary Ann McNamara formeley Linskey both were born in Liverpool England
Thank you
John McNamara