Massac County, established in the year 1843 was named in the honor of Fort Massac, a colonial-era fort on the Ohio River. It has the county seat and the largest city in Metropolis. With a total area of 241.81 sq mi, it consists of over 15.4K people with a racial makeup including White, Native American, black or African American, Asian, Hispanic or Latino, Pacific Islander, and others with more than 6.2K households and 4.3K families. The County is situated on the Ohio River in Illinois, USA, in that portion of the state known locally as "Little Egypt".

The County records website of the Massac County not only provides the required information on origin and birth certificate numbers, marital status and divorce decree information, census index including ancestral Social Security Numbers, land allocation deeds, military service and recruitment details, adoption history, American civil wars and World War I & II records, last will and estate reports, probate data with civil lawsuit information and lots more but also furnish the genealogical researches and online historical explorations with ample amount of data.