Louth is the site of an amazing and emotive structure known as 'The Celtic Cross'. The Cross is a seven-metre (24-foot) polished granite cross that dominates the cemetery on the hill overlooking the town. It was constructed by the founder of Louth, Thomas Mathews, who erected the monument as a perpetual memorial to his wife, Mary Mathews, who died in 1866.

Every year on the anniversary of her death, August 19, the sun reflects from the Celtic Cross to the front door - the spot where their house, The Retreat, once stood. Anyone visiting Louth can observe the occurrence, and the locals have thoughtfully marked the places where visitors can experience the three-minute light show.

The monument is not only a testament to the love and devotion of a husband for his wife but also to the accuracy of navigation technology of the 1800s. Its alignment was reportedly aided by one of the riverboat captains of the Darling River.

Anyone visiting Louth can observe the occurrence, and the locals have thoughtfully marked the places where visitors can experience the three-minute light show.

In 1866 Thomas Mathews purchased 200 acres, of which 40 acres were divided up into house blocks along the Darling River. He also built a bonded store where goods could be stored. Around this time, he became known as the 'King of Louth'.