The road known as state highway number seven, extending along the Ohio river between Cincinnati, Ohio, and Gallipolis, Ohio, and through the counties of Hamilton, Clermont, Brown, Adams, Scioto, Lawrence, and Gallia and through the municipal corporations of Cincinnati, New Richmond, Neville, Higginsport, Ripley, Aberdeen, Manchester, Portsmouth, Ironton, Proctorville, and Gallipolis is designated as “the Atlantic and Pacific highway”. In Rome township, Lawrence county, the said Atlantic and Pacific highway shall follow state highway number five hundred and nine instead of number seven.