Loughcrew has received a significant amount of historical importance in Ireland. Loughcrew is perhaps the oldest passage tomb in the world. The cairns are possibly older than the tombs at Brú na Bóinne. The site dates back to approximately 3500 B.C. However, there are tombs that are believed to date back to around 3300 B.C.

The tombs are located on three different hills and the largest tomb is the primary focus of Loughcrew. One of the popular smaller tombs is called Cairn L and the largest tomb is known as Cairn T. There are about twenty-three tombs besides Cairn L and Cairn T in Loughcrew. Inside the tomb are stunning examples of Neolithic art and a cruciform chamber with a corbelled roof.

One of the incredible secrets of Loughcrew involves the Equinox Illumination at sunrise. This is when the stones in back of the tomb are illuminated by sunrays similar to Newgrange and Dowth during the Winter Solstice.

The hills are also referred to as Sliabh na Caillighe, this translates to "Mountain of The Witch". The myth suggests that these impressive burial mounds were made by a witch dropping stones on the landscape from overhead.