Fort Worth is the 16th-largest city in the United States and the fifth-largest city in the state of Texas. The city is located in North Central Texas and covers nearly 30 square miles (78 km2) in Tarrant, Denton, Parker, and Wise Counties; it is the seat of Tarrant County.
The Treaty of Bird's Fort between the Republic of Texas and several Indian tribes was signed in 1843 at Bird's Fort in present-dayArlington, Texas. Article XI of the treaty provided that no one may "pass the line of trading houses" (at the border of the Indians' territory) without permission of the President of Texas, and may not reside or remain in the Indians' territory. These "trading houses" were later established at the junction of the Clear Fork and West Fork of the Trinity River in present-day Fort Worth. At this river junction, the U.S. War Department established Fort Worth in 1849 as the northernmost of a system of 10 forts for protecting the American Frontierfollowing the end of the Mexican–American War. The City of Fort Worth continues to be known as "where the West begins."