Ardrossan signifies a rocky height, terminating at a rocky point in the sea, from Ard, a height; & rossan, a small peninsula. Ardrossan is indicated in a map of Scotland of the thirteenth century.

The date of the building of the castle was probably about 1140, and it was owned by Simon de Morville, later passed on to the de Barclay Family (also known as Craig), then in the 13th century it came to Arthur de Ardrossan, after came a succession of knights who became heirs to the castle. The Barclays were the owners of the castle and estate during the 12th, 13th, and 14th centuries, until the death of Godfrey de Ardrossan. He died without leaving a son and the estate passed by marriage to the Eglinton family.

The castle was designed on the 'Courtyard Plan' as a defensive structure, surrounded by a man made ditch on a motte, and a steep natural slope down to what was then the sea shore. Made from local red sandstone or freestone the walls vary from one to two metres thick.

Richard Barclay de Ardrossan witnesses granting of charter to Kilwinning Abbey.

Baecon Tower was erected on Horse Isle by Hugh, Earl of Eglinton, at the instance of the celebrated Artic explorer, Sir John Ross.

A number of iron rings were found attached to the rocks at the foot of the Castlehill by which boats were frequently moored, indicative of the water level during the 12th century.

Arthur Barclay de Ardrossan witnesses granting of land of Monnoch in Dalry Parish to Hugh Crawford.

King Hakone's fleet emerging from Lamlash Bay, behind Holy Isle, and sailing north towards Largs to do battle with King Alexander of Scotland, an armament of 120 vessels. Hakone's own ship having 27 banks of oars.

The Spanish Armada sailed up the Clyde after being defeated by Drake. Many ships were wrecked in a violent storm, one on the rocky shore at Portencross Castle, on that ship seventeen men survived including the captain, the survivors were provided with food drink and lodgings, many Spaniards eventually stayed in the area.

Cromwells troops destroyed the castle; taking much of the stonework by boat to Ayr to build the Fort there. All that remains are part of the walls, a portion of one of the towers, a vaulted kitchen and two cellars. The castle is shown on the Ardrossan coat of arms as having three towers, but this cannot be proved and may just be simply following the traditional heraldic depiction of a castle.

The Eglintons took refuge in " Sma Cumbrae Castle ". (The Eglintons returned in 1813 to a mansion called The Pavilion, later demolished in 1930, the site where St Peters Church now stands.)

The Parochial Church of Ardrossan, which stood within the grounds of the graveyard overlooking the seashore, was blown down by a hurricane and never restored. In it were altars to St Peter and the Virgin Mary. It was excavated in 1912, when it was shown to be a long, oblong building , its chancel of the same width as the nave, above which it was raised by three low steps, placed at wide intervals. Considerable areas of stone paving remained. A stone coffin, with a carved lid, was found within the church, near the N wall. It was removed and is now in the North Ayrshire Museum in Saltcoats. A 13th century date is suggested for it.

The Second Parochial Church was built 3/4 of a mile NE of the castle on the right bank of the Stanley Burn near Stanley Clachan. Minister Rev. Mr Thomas Clarke. The only memorial or trace of this church is the tombstone of this minister, who was buried within the precincts of the church. This small monument was erected after the church had been translated to Saltcoats.

Glasgow Street building started.

Hugh, the 12th Earl of Eglinton was raised to the British Peerage as Baron Ardrossan.

Eglinton Arms Hotel built.

Extensions to the harbour and dockyard.

Ardrossan Pier Station. Ardrossan and Johnstone Railway opened. This station formed the terminus of the Ardrossan Harbour branch of the Glasgow and South-Western Railway and opened (as Ardrossan Pier Station) by that company on 27 July 1840, was renamed Ardrossan Winton Pier Station on 2 June 1924 and closed to regular passenger traffic on 6 May 1968. The new (British Rail) Ardrossan Harbour station was opened on the same site on 19 January 1987 and remains in regular passenger use.

Free Church organised.

Trade with Belfast begun.

Ardrossan and Johnstone Railway acquired by Glasgow and South-Western Railway 31st July.

Kirkhall Cist. A cist, built of six stone slabs, oriented E-W, and measuring about 24 ins by 16 ins and 12 ins deep, was found in 1856 on the lands of Kirkhill, Ardrossan. It contained fragments of burnt bones and wood charcoal, accompanied by a food vessel, now in the National Museum of Antiquities of Scotland

Royal Bank succeeded the Western Bank in Ardrossan and Saltcoats. Agents: John Jackson and R. King Barbour.

New church erected in Harbour Lane.

Rock face removed at the castle to give greater accommodation to the Railway reveals human remains, a number of bodies were found in these "cists". (Stone tombs). In each case the bones lay head to the west & feet to the east, and armbones alongside thighbones, age estimated 600 years plus.

4th May. Gas and Water Works bought by the town.

Union Bank opened - 27th July 1887. Agent William Crichton

First pile in the construction of Eglinton Dock driven, 4th May 1887. Contractor, Mr Lawson.

Lanarkshire & Ayrshire Railway opened 3rd September. It was called Ardrossan Station and was renamed Ardrossan Town Station on 1 October 1906, closed on 1 January 1917 and reopened on 1 February 1919. It was renamed Ardrossan North Station on 2 June 1924, and closed to regular passenger traffic on 4 July 1932.

Barr & Shearer commenced the building of the first iron vessel at the yard. They were repairers and builders of vessels of a moderate tonnage.

Power House at the Dock opened.

Clydesdale Bank Opened - 1st July 1892. Agents John Hoggarth & Son.

Excavations of the Parish Church on Castle Hill brought to light a beautifully carved stone coffin said to be one of the finest examples of its kind in Scotland. It is probable that in it was buried one of the Barons of Ardrossan. It is now on show in the North Ayrshire Museum, Saltcoats.

1st September - Board of the Ardrossan Dry Dock & Shipbuilding Company Ltd. changed transferring the whole of the interests to the Clyde. NORTH DOCK developed with vessels launched into a wet dock.

First World War, HMS Pactolus was placed in the harbour to care for submarines. A pier was modified (Montgomerie Pier) with 3 x 6000 ton fuel tanks, pipes and pumps for refuelling.

The first 5 vessels that were launched from the south yard were:- SS Hunstanworth 2580 gross tons; SS Glassford 2580 gross tons; SS Poljana 3886 gross tons; SS Dunkerquois 3160 gross tons and SS Skrymer 1990 gross tons.