This thesis is a study of the growth, development, fortunes, and subsequent decline of the United Irish League (UIL) in the King's county between 1899 and 1918. This organisation carried out many tasks for the Home Rule or Irish Parliamentary Party (IPP), such as collecting party funds, registering voters, organising demonstrations, canvassing voters during elections, and solving disputes between Nationalists. Historians have tended to examine the defeat of the IPP in the General Election of 1918 in the light of events that unfolded after 1914 (and more particularly after the Easter Rising), but this thesis shows that the party's structures at local level (ie the UIL organisation) was in a chaotic state as early as 1912; and consequently, the rise of Sinn Fein after 1916 took place in a background of much less opposition than might have been anticipated. The first two chapters in the thesis examine the early growth and development of the movement in the county, which was not entirely a smooth occurrence for a number of reasons. Particularly striking here was the general wave of apathy prevalent in the county after the Parnellite split in 1890, and while the deposed leader had little concrete support in the county, the absence of moderate opinion regarding the crisis meant the bitterness that resulted remained longer than might otherwise have been the case. Existing Nationalist organisations at this time like the Irish National League, Irish National Federation, and the GAA, all suffered from the dispute; while the resultant loss in the confidence of the divided Irish Party at Westminister more than anything else helped to give the IRB a boost in its membership in certain parts of the country at this time. Even after the UIL had established strong roots in Connacht, the new organisation had difficulty making its presence felt in the King's county, and this can be accounted for by the absence of strong clerical support at first for the movement; plus the added fact that the counties two MP's in 1899 failed to join or espouse its principles. This meant paid organisers had the task of establishing branches, but the prudent decision of the RIC not to proclaim any of its meetings or arrest any of its leaders meant the UIL had to work hard to gain publicity for its principles. Even after the formation of the branches in 1899 and 1900, many Nationalists were reluctant to join the movement, and this may be accounted for by the contradiction of aims within the UIL movement, particularly in relation to the grazing or 11- months system of land holding. Chapters three and four deal mainly with agrarian matters, most notably, the effects of the Wyndham Land Act and the Ranch War of 1906-1909. It is argued in the thesis that both had long term implications for the UIL's strength, which may have been unnoticed by Party leaders and MPs at this time. While the Wyndham Land Act was generally welcomed at first in the county, and resulted in many tenants rushing to purchase their holdings, many disputes emerged over the rights of the evicted tenants which had profound implications for some of the UIL branches in the county. Likewise, the Ranch War was also responsible for creating divisions among Nationalists, particularly in relation 1 to the stoppage of the Ormond Hunt, the result being that after 1908 the UIL began to lose support that would culminate in the IPPs defeat in 1918 General Election. The second half of the thesis examines in detail this slip in support for the UIL. The role played by the county's two MPs, Michael Reddy and Haviland Burke, in this are examined, while the National Directory's failure to check this decline deserves special attention. The defeat of the UIL's candidate in the Tullamore by-election of December 1914 may have come as a shock to the IPP, but should not, as the UIL was in very poor shape throughout the county by this time. Attempts to reorganise lapsed branches afterwards in 1915 were hamstrung by the UIL's links to the IPP, for the latter's support for Britain in the War resulted in many decisions which became increasingly unpopular as the conflict dragged on until 1918. The most notable examples here include the recruiting campaign; the malting and liquour restrictions; the many grievances of farmers, such as the commandeering of hay, oats and wool; fixing of cattle prices; the Equalisation of Time Act; and the tillage regulations of 1917. Allied to all this was the change in public opinion in the aftermath of the 1916 Rising, which had an important prelude in the county in the "Tullamore Affair" that March; while the IPP lost more support due to its involvement in the failed Irish Convention of 1917-1918. Meanwhile, during 1916 and 1917, the UIL continued to decline at local level and this is reflected in the amount of funds collected by the organisation which also declined from 1908 onwards, while the reported number of League meetings held in the county from 1915 shows a similar pattern. Sinn Fein activists meanwhile, worked hard to establish branches in the county from 1917 onwards and cleverly exploited local issues like the tillage crisis to gain the movement support. In turn, the fact that the majority of the clergy threw their support behind the party, helped to give it a respectability it might otherwise have lacked. When all these factors are taken in conjunction, it was not surprising that the IPP was more than willing to withdraw its candidate from the north King's county by-election of April 1918; a decision taken in disgust at the Government's decision to pass the Military Conscription Act earlier that month, but made easier by the total break down of the UIL in the constituency. Much more local study of the UIL in other counties is needed to see if a similar development took place in other parts of Ireland, for this thesis shows the League was simply not fit for electoral challenges in the King's county after 1912. In many respects the King's county proved to be the political graveyard of the IPP, for the defeat of the party's candidate in the Tullamore constituency in December 1914 after the apparent securing of Home Rule was a major blow to the party at that time; while the party's decision not to contest for the same seat again in April 1918 marked the point of no return in its electoral fortunes.