In 1858 the Texas legislature formed Duval County, which originally embraced 1,887 square miles, from parts of Nueces, Live Oak, and Starr counties. County organization did not occur until eighteen years later. The county was named for Burr H. Duval, who fought in the Texas Revolution and was killed in the Goliad Massacre. Duval County lost a portion of its land, including the town of Hebbronville, when Jim Hogg County was formed in 1913.
Shortly thereafter, Parr made two additional attempts to divide Duval County. Through the establishment of Pat Dunn and Lanham counties he apparently hoped to increase the patronage jobs and tax revenue at his disposal, but he was foiled both times.
Though Pat Dunn County never existed, it is a vivid illustration of the tactics of the founder of the most notorious political dynasty in Texas. In 1913 state senator Archer Parr, the political boss of Duval County, came up with a scheme to double the amount of political patronage and revenue sources at his disposal. He proposed dividing Duval County roughly in half and turning the southern portion into a new county. In January 1913 he introduced a bill proposing the formation of Ross County, but protests by Duval County residents and the opposition of powerful Starr County rancher Edward C. Lasater doomed the bill to failure. Later in 1913, however, during a special session of the legislature, Parr caught his opponents off guard and secured the passage of another bill calling for the establishment of Pat Dunn County, named after a Corpus Christi legislator who was one of Parr's political allies. The Parr forces attempted by gerrymandering tactics in the December 1913 election to choose the seat of the new county; they deprived Realitos, the ranching town that was Lasater's Duval County headquarters, and Concepcion of their voting boxes in an effort to ensure that Parr's hometown, Benavides, would be chosen. These blatant tactics resulted in an injunction blocking the election. Parr's supporters proposed an alternate precinct plan that was no improvement, with the same result. Before they could try again, it was determined that the legislation authorizing Pat Dunn County violated an obscure provision of the state constitution that requires a distance of at least twelve miles between the boundary of a new county and the seat of an existing county (the town of San Diego, in the case of Duval County). Despite the failure of Pat Dunn County, Parr was not quite ready to abandon his scheme. He introduced another county-formation bill in 1914.
This one passed the Senate, but failed in the House after Parr offered some injudicious testimony regarding his influence over Duval County politics. He tried again during the May 1915 special session, but this bill also failed in the House. Thereafter Parr concentrated on solidifying his power in Duval County, a task in which he met with conspicuous success.
-Handbook of Texas Online: Pat Dunn County