The soft soil and low-lying geography result in consistent coastal erosion that threatens some of the infrastructure of the community.

The topsoils are fine and loamy, whilst the rock beneath the boulder clay is classed as Flamborough Chalk from the Upper Cretaceous period.

[8] Historically large stones in the boulder clay were removed for use in road construction – this activity had been prohibited at Hornsea by the board of trade by 1885.

[11] Since at least the late 19th century the geological conditions overlying the underlying chalk have been interpreted as being from a glacial process in origin – both the boulder clay and the gravel beds and moraines.

[12] Borings suggest the chalk probably lies at around 60 to 70 feet (18 to 21 m) under the sand, gravel and clay beds at Hornsea, though possibly deeper.

[13] It is thought the source of the submarine forests recorded on the coast at Hornsea may have been a second mere on the eastern side of the present lake which was silted and was lost to the sea at some point.

Near Norththorpe, north of Hornsea crop marks indicate a site interpreted as a Neolithic henge monument, thought to have been later reused as a Bronze Age ringwork.

[34] There are also cropmarks in the Hornsea area indicating human activity during the Iron Age/Roman Britain period, thought to the remnants of field systems.

[39][40] Drogo fled to Flanders c. 1086 after killing his wife, a relative of William the Conqueror, and Holderness subsequently passed to Odo, Count of Aumale.

In around 1088 Odo gave the manor, church and lands at Hornsea to the Benedictine St Mary's Abbey, York.

The font, some memorials and an effigy also date to the 13th century,[43][44] a restored former medieval market cross is found in the churchyard.

[47] The church was extensively restored in the 1860s by George Gilbert Scott, including rebuilding of the upper tower; further work was done at the beginning of the 20th century by Brodrick, Lowther & Walker.

[44] The medieval rectory of the church was located to the north, at a moated site – some earthwork remains are still extant, and were incorporated into the public Hall Garth Park in the 19th century.

[60] In 1732 the town was struck by a 'hurricane' which in addition to destroying the church's spire, unroofed around 40 buildings, as well as causing part of the vicarage to collapse, and overturned one windmill.

[63] The Old Hall in Hornsea Market Place dates to the early 17th century, and is built of brick on cobble foundations.

[6] By the mid 19th century Hornsea comprised three main streets at the eastern end of the Mere – Westgate, Southgate and Market Place; two streets, Newbegin and Eastgate led eastward towards the sea from Market Place, merging around 200 yards (180 m) from the cliff – the land east of Hornsea town towards the sea was in agricultural use.

[74][75] Hornsea was promoted as a seaside resort from around 1800, with early attractions including bathing machines, horse races on the beach and a chalybeate spring near the mere.

[77] In 1861 a company was formed to promote railways in the East Riding of Yorkshire, and obtained an act for a 13 miles (21 km) line from Wilmington, Kingston upon Hull to Hornsea in 1862.

Joseph Armitage Wade, a Hull timber merchant and Hornsea resident was a key promoter of the line.

[76] There was significant growth in the small scale fishing that took place at Hornsea before the railway – persons recorded as Fishermen rose from 3 in 1851 to a dozen or more in the 1870s to 1890s, with 12 boats and 20 men recorded in 1894 – crab was the major catch, rather than wet fish – crabbing continued to the 1930s but declined after the Second World War.

The coming of the railway was followed by further development, including Alexandra Hotel (1867); Wilton Terrace (1868); the high status dwellings Brampton House (1872–73); and the Grosvenor Estate, built during the period from 1865 to the early 20th century.

There was also a short lived brickworks north of the mere, and sand and gravel extraction also took place in the parish, as well as lime kiln activity.

[88][89][90] Other notable mid 19th century additions to the town include the two storey three bay vicarage on Newbegin; the stuccoed Pike and Heron public house (c. 1830);[91] a Primitive Methodist chapel in the Market Place built 1864;[92] a Gothic Revival style non-conformist Congregational church on Hornsea Cliff Road/New Road, built 1868;[93][94] and the Wesleyan church and adjacent church hall on Newbegin, built 1870, replacing the one in Back Southgate.

The timber defences were destroyed or damaged by the storm with most of the beach swept away, and a large amount of cliff eroded exposing the underlying clay.

The new defences at Hornsea were constructed north of New Road protecting the seafront at Marine Terrace and Victoria Gardens.

[98] The early 20th century house, 'Farrago', on Wilton Road, built with a bolted steel frame with brick and stone dressing by builder David Reynard Robinson is now listed.

[105] During the Second World War Hornsea was fortified with numerous anti-invasion structures, designed to prevent a beachhead being established at Hornsea by invading forces – beach defences consisted of pillboxes flanking the promenade, whilst the beach was protected by anti-tank cubes and mines; at South Cliff 4.7-inch guns were installed.

[106] Many of the predominantly reinforced concrete structures are no longer extant, the recorded defences include: coastal beach defence batteries, with 4.7-inch gun batteries,[107] other gun emplacements,[108] numerous pillboxes,[109] road blocks and road and railway antitank obstacles, including extensive anti-tank cubes on the beach,[110] Royal Observer Corps posts,[111] weapons pits and/or infantry trenches,[112] barbed wire protected trackways[113] and Army camps and associated facilities,[114] including a camp "Rolston camp", located east of the Hornsea Bridge suburb on ground now destroyed by coastal erosion, with associated infantry trenches, grenade ranges, strongpoints and minefields,[115] some farm buildings were also fortified.

[116] Other Second World War structures also included air raid shelters,[117] and 'Diver' anti-aircraft battery designed to destroy V1 flying bombs.

Hornsea Beck was a small village or hamlet close to the sea – it is recorded in existence as early as 1367, and had been completely destroyed by the coastal erosion by c. 1747.