The city is known for the sacrificial knife, the Tumi, that was discovered in the Batán Grande Reserved Zone by archeologist, Julio C. Tello, in 1936.

More recently in 1996, archeologist, Walter Alva, found the tomb of Guillermo of Illimo, that included the first discovery of Lambayeque clothing which, at the time, had only been known based on iconography depicted on previously excavated pottery.

According to legend, the Lambayeque region was founded by the mythological Naymlap, who led a crew of nine foreign warriors into northern Peru, on a fleet made of Balsa rafts.

Several centuries later, the same territory would belong to the Chimú culture, beginning around 900 AD; on the cusp the Middle Horizon and Late Intermediate period.

Years later in 1894, the marshall Andres Avelino Caceres, created the legal jurisdiction of Tucume, that annexed Illimo.

Finally, on the 22 of November, 1905, Illimo once again gained its independence as a legally established district of the Lambayeque Region of Peru.

Since 1878, the town of Illimo has held a festival in honor of the Child God of Kings, Jesus Christ, on the 4th, 5th and 6th of every January.