The area of Tallong was once known as Barber's Creek, named after George Barber who was the pioneer of the district. He came from the Isle of Wright, and arrived in July 1814 followed by his mother after the death of her husband. She later married Dr Charles Throsby. George then married Isabella Hume and settled in the Campbelltown area.

On the 30th of March, 1821, George obtained a permit to send cattle and a stockman to the country "south and west of the Bargo Brush". John Mulligan was in charge of the 56 head of cattle. On the 31st of March 1821, Governor Macquarie promised George a grant of 300 acres, which he took up in what is now known as the Tallong-Marulan district. He ended up owning almost 4000 acres, which he named "Glenrock".

In June 1844 George was returning home from Goulburn when he fell off his horse whilst crossing the Wollondilly River and drowned. His body was recovered 11 weeks later and than buried at the Old Marulan cemetery.

In 1900, the fruit growing industry was established and in 1915, Tallong was making progress as one of the most prosperous orchard districts in NSW. in the following months, more land was being reclaimed from the wilderness, and over 3000 trees had been planted. In 1926 the industry was still prospering and the local orchardist, E Carter, built cool stores to house 8000 cases of fruit.