Dial Post was part of the "West Grinstead Hundred" so called since 1334. From the 16th Century it was then known as the "Grinstead Hundred". Dial Post descended with the Bramber Rape. In 1403, Eliazabeth, widow of Thomas Mowbray, Duke of Norfolk and wife of Sir Robert Goosehill held it in dower, like West Grinstead Manor.

The Hamlet of Dial Post occupies a knoll of land on the Horsham to Worthing road, in the western part of the parish. Dial Post Farm, Dial Post Fields and Dial Post House were named in the early 18th Century. The name "Dial Post" was applied later to the settlement which grew up along the road during the 18th and 19th centuries and which in the early 19th century was called a small village.

By 1840, there were eight to ten houses in the hamlet including an early 19th century villa at the north end. After 1920, some council houses were built on the North side and new houses and bungalows were built in the south west. In 1974 the Hamlets population was 230.

Stock Park was situated in the West of Dial Post. It was a large area belonging to the Braoses and descended with Knepp Manor in Shipley from the 13th Century until the 17th Century. There was a barn (Grangia) called Stock in 1210. In 1255 various tenants of William De Braose were released from their suit at his Hundred Courts in exchange for yielding up their right of chase in his lands at Stock and Hookland in Shipley. Braose was granted Stock Park in 1281. When he died, his widow, Mary, who died in 1326, held Stock in dower. It was a park of 200 acres belonging to West Grinstead Manor. Stock comprised of 24 acres of woodland in 1425. Between 1448 and 1449, payments were made to the carpenters cutting down the timber and taking it to Washington. In the late 15th Century the Park was leased to John Gratwicke, who died in 1564. He was succeeded by his son and grandson; both were called William. In 1576 Richard Nye owned it when he died in the same year. In the early 19th Century, around 1806, Sir Charles Burrell owned land called Stocks Common, and part of the estate and field called Stock Park. Stock Park House, which was possibly a lodge, was built around 1618.