Highway 304 was added to the state highway system as part of a large transfer of county roads to the state system that took place on April 24, 1963.[1] Initially only the portion from US 67 to the Greene County line was transferred to state maintenance.
^ abcdPlanning and Research Division (2010). "Arkansas Road Log Database". Arkansas State Highway and Transportation Department. Archived from the original(Database) on June 23, 2011. Retrieved June 9, 2011.
^ abGeneral Highway Map, Randolph County, Arkansas(PDF) (Map). 1:62500. Cartography by Planning and Research Division. Arkansas State Highway and Transportation Department. 2009. Retrieved November 5, 2011.
^ abGeneral Highway Map, Greene County, Arkansas(PDF) (Map). 1:62500. Cartography by Planning and Research Division. Arkansas State Highway and Transportation Department. 2008. Retrieved November 5, 2011.
^ abMap of Pocahontas, Arkansas(PDF) (Map) (September 2004 ed.). Arkansas State Highway and Transportation Department. Retrieved March 20, 2011.