As recently as 1800 the parish of Milford was entirely inland, being separated from the sea by a narrow strip of coastline which was an extension eastwards of Hordle parish. Coastal erosion, as well as the growth of the village to the south and west, meant that by 1900 Milford bordered the sea. Milford was part of a combined Milford and Pennington Parish Council after 1894. In 1905 it gained the Hordle coastline strip. In 1911 Milford and Pennington separated into two different civil parishes and Milford became known as Milford on Sea. In 1932 Milford was absorbed into an enlarged Lymington Municipal Borough, only reemerging as a separate parish in 1974.
The post-1974 Milford is a civil parish in the New Forest District of Hampshire. At the 2011 Census the population of this ward was 4,838. Its primary settlement is the large village of Milford on Sea (often hyphenated as Milford-on-Sea) located on the shore of the Solent. The Solent is the body of water separating the Isle of Wight from the mainland of Hampshire.
The parish includes Hurst Spit, approximately two miles of shingle, from the end of which the inhabitants of Hurst Castle used to watch over the Solent. The castle was built by Henry VIII as part of the protection for the harbour of Southampton.
At the time of the Domesday Book of 1086 there were two separate estates in Milford, one held by Aelfric Small, and the other some unpopulated land held by Wulfgar. At a later date three separate manors were evolved from these estates and were eventually known by the names of Milford Montagu, Milford Barnes, and Milford Baddesley. (The ownership of each of these estates is briefly covered in Wikipedia and in depth in the article on Milford in Victoria County History of Hampshire, volume 5.)
Around 1800 Admiral William Cornwallis (brother of Charles Cornwallis) leased and later purchased the small Newlands estate in Milford. His purchases included the manors of Milford Montague and Milford Barnes. He was joined at Newlands by his close friend and fellow naval officer Captain John Whitby and John's wife Mary Anna Theresa Whitby. John Whitby died in 1806, but Mary and her infant daughter Theresa stayed on looking after Cornwallis into his old age. On William Cornwallis' death in 1819, Mary Whitby and her daughter inherited his fortune.
In 1829 Mary Whitby purchased Milford Baddesley, thus uniting all the estates in the area. Her daughter Theresa, who inherited the estates, married Frederick Richard West, and they used Newlands as one of their residences. Their son, born in 1835, bore the name of William Cornwallis-West. He inherited Newlands in 1886, and attempted to convert Milford into a premier seaside resort, changing the name of the village to Milford-on-Sea. All his plans did not come to fruition but it gave Milford a layout and ordered development that lasted well into the 20th century.