Governor Lachlan Macquarie issued land grants in 1810 to encourage settlement in the Mulgoa Valley. Soldier and road-builder William Cox built his cottage the following year. The building still stands today.

Cox’s sons, George, Henry and Edward, established farms adjoining their father’s property and in 1836 they became members of a committee to build a church nearby. Their commitment to the community saw them offer portion of their land to accommodate the church and rectory. Sandstone was quarried on the Fern Hill property and Bishop Broughton consecrated St Thomas’ Church on 13th September 1838 with Rector Thomas Cooper Makinson occupying the rectory.

The church organ is one of the smallest in the country supplied in colonial times by John Walker of London. It has four ranks of pipes and was originally operated by hand pumped bellows which are still in working order. An electric airpump was installed around 1946.

The stained glass window was given in memory of George Cox in 1868 with the wording of the English township of Wimbourne, William Cox’s birthplace.

The bell in the tower was cast in England and brought to Australia in 1856 packed in wheat which was later sown in the area. The inscription on the bell reads ‘Glory to God in the Highest’.

The cemetery beside the church dates from early 1838 with many pioneer families including Norton, McLean and Cox.