Washington county, Ohio is code 84. Ohio has 88 counties and the number goes in alphabetical order. Ohio went back to the county name on the plate in 2018.
NEWS Flash : Ohio no longer issues or requires a front licence plate on most vehicles as of July 1st, 2020.
Ohio offers a 5 year registration sticker for personal vehicles or anything between 1-5 years as desired. Few people choose more than one year.