"COUNTY DUBLIN, a maritime county in the province of Leinster, Ireland, lying between 53° 11' and 53° 37' N. lat., and 6° 3' and 6° 32' W. long. It is bounded N. by the county of Meath, E. by the Irish Channel, S. by Wicklow, and W. by Kildare and Meath. Its greatest length N. and S. is 32 miles, and greatest breadth E. and W. 18 miles; and it comprises an area of 222,709 acres, exclusive of Dublin city. The earliest inhabitants of this district of whom we have any authentic account were a people designated by Ptolemy Blanii or Eblani, and whose capital city was Eblane, presumed to have been on the site of the present town of Dublin. These people, in all probability, enjoyed peaceable possession of the land till the invasion of the Danes in 845, when Dublin was seized, and its inhabitants slaughtered or subjected. From this period there was incessant war or pillage between the Danes of Dublin and the Irish, which only terminated in the celebrated battle of Clontarf, 1014, where the Irish, under Brian Boru, completely overthrew the Danish power in Ireland. Deprived of their national character, the Danes gradually merged into the mass of the native races. Nearly the whole of the county N., of the Liffey was in their possession, and, from this circumstance, was named by the Irish Fingall, signifying "white foreigners," or, "progeny of foreigners;" but, owing to the number of other proprietors, and from its being the centre of the English power in Ireland, it never became placed under palatine or other peculiar jurisdiction.
It was made shire ground by John in 1210. The authority of the Sheriff of Dublin appears to have extended far beyond its present limits; for at the close of the thirteenth century, by an ordinance of parliament, it was restricted from extending, as previously, into the counties of Meath and Kildare, and even into some parts of Ulster. It is in the diocese and province of Dublin, and for purposes of civil jurisdiction is divided into the baronies of Balrothery, Castleknock, Coolock, Nethercross, Newcastle, Half Rathdown, and Upper Cross. It contains 83 parishes, of which 7 are in the city, and a population of 152,289, according to the census of 1861. The county is fertile and well cultivated. Those portions not under cultivation are the promontory of Howth and the range of mountains separating Dublin from Wicklow on the S. The mountains occupying the southern portion of Dublin are-the northern extremities of the great group forming the adjacent county of Wicklow, of which the principal summits within its confines are the Three Rock Mountain, 1,586 feet, and Garrycastle, 1,869 feet; Montpelier Hill; the Kippure range; and the Tallaght and Rathcoole hills-the whole mass forming a fine mountain background to the rich scenery of the plain of Dublin. The northern part of the county is more undulating than the immediate vicinity of the capital. A low group, called the Man-of-War hills, extends across the line of communication with Meath and Louth. The only marked eminences N. of the mountainous tract are the islands of Lambay, Ireland's Eye, and the Hill of Howth. The cliffs towards the bay and channel are lofty, and the whole promontory contributes greatly to enhance the picturesque effect of Dublin Bay. The coast has a length of 70 miles, and is indented by the bay of Dublin and the creeks of Killiney, Malahide, Rogerstown, and Lough Shinny. Artificial harbours have been formed at Balbriggan, Kingstown, and Howth. Off the coast is the island of Lambay and the islets of Red Island, Coll Island, St. Patrick's Island, Shinnick's Island, Ireland's Eye, and Dalkey. -The only river of importance is the Liffey, which, rising in the Wicklow mountains, takes a westward circuit through Kildare; is joined by the Rye water on entering Dublin; and after pursuing a winding course, finally discharges its waters into the bay of Dublin. The climate is temperate; frosts rarely continue more than a few days, and snow seldom lies. Its manufactures are various, but of inferior importance. The numerous small streams by which the county is watered afford advantageous sites for the erection of manufactories. The great extent of sea-coast presents facilities for obtaining an abundant supply of fish. Salmon, herrings, whiting, and pollock, are caught in great quantities at the various seasons of they ear. The county returns two members to the imperial parliament. A court of assize is held every six weeks at the court-house in Dublin. The local government is vested in a lieutenant, 17 deputy lieutenants, and 88 magistrates, with the usual county officers. In military arrangements the county is the head of all the districts throughout Ireland. There are 8 coastguard stations, 26 martello towers, and 9 batteries on the coast, capable of containing 684 men. The internal communication of Dublin is excellent. It is traversed in a westerly direction by the Royal canal and the Grand canal, both of which carry on an immense traffic. The main roads are those to Howth, Malahide, Drogheda, Ratoath, Navan, Mullingar, Enniskerry, Bray, and Kingstown. The railroads traversing the county are the Dublin and Drogheda line, with a branch to Howth; the Great Southern and Western; the Midland Great Western; the Dublin, Wicklow, and Wexford; and the Dublin and Kingstown. Pagan antiquities are not numerous. There is a cromlech in Howth; another to the S. of Killiney; and a third, of larger dimensions, at Brennanstown. There are some so-called Druidical remains on the commons of Dalkey. It is rich in ecclesiastical and military relics. Among them may be mentioned the round towers of Clondalkin, Lusk, Shankill, and Ireland's Eye; the antiquities of Swords, consisting of a palace of the archbishops of Dublin in ruins, a square steeple of the old church, and a round tower 73 feet high; and the hamlet of St. Dowlagh's, one of the most singular stone-roofed churches in Ireland. The castles of Clontarf, Baldangan, Naul, and Castleknock, are chief military edifices. Among the minor natural curiosities are some chalybeate springs. The principal towns are-Kingstown, Balbriggan, Rathmines, Skerries, Blackrook, Donnybrook, Ringsend, and Sandymount. Of the principal seats of the nobility and gentry, the best known are: Phoenix Park, the palace of the lord-lieutenant; Howth Castle, of the Earl of Howth; Blackrock, of Lord Cloncurry; Bray, of the Earl of Meath; Blessington, of the Earl of Milltown; Marino, of the Earl of Charlemont; Cabra House, of the Earl of Norbury; also Redesdale and Tallaght, seats of the archbishop. At Glasnevin is a botanic garden and cemetery. At Kilmainham the Templars had a preceptory."