Tolu is an unincorporated community and census-designated place (CDP) in Crittenden County, Kentucky, United States. As of the 2010 census it had a population of 88. It is located along Kentucky Route 135 near the Ohio River. It is 14 miles (23 km) northwest of Marion, the county seat.

The primeval known deal in what became the well ahead town of Tolu was the Native American prehistoric archeological site of the Mississippian culture, known today as the Tolu Site was built and occupied together with 1000 CE-1350 CE.
This far along culture flourished in chiefdoms along the Ohio and Mississippi rivers, reaching its height in size and talent at Cahokia in present-day Illinois, the largest prehistoric highbrow north of Mexico. Peoples of the culture had wide trading networks spanning the continent along the Mississippi River, from the Great Lakes to the Gulf of Mexico.

The Tolu Site is portion of the Angel phase of the Mississippian period. Because of similarities accompanied by the once sites in their styles of pottery and construction of communities, it is furthermore considered part of the “Kincaid Set”, together later than Angel Mounds in Indiana and Kincaid Mounds in Illinois, and Wickliffe Mounds in in the distance western Kentucky.

By 1800, a small river front settlement developed that would forward-looking become Tolu, Kentucky and was for a period known as Kirksville.