Eagle Pass, the county seat of Maverick County, is located on the Mexican border at the intersection of U.S. highways 277 and 57, Farm Road 1021, and the Southern Pacific Railroad in the far western part of the county. During the Mexican War a company of Texas Mounted Volunteers under the command of Capt. John A. Veatch established an observation post on the Rio Grande opposite the mouth of the Mexican Río Escondido and beside an old smuggler's trail that crossed the river at this point. The crossing, known as El Paso del Águila, was so named because of frequent flights of Mexican eagles from the wooded grove along the Escondido. Though abandoned by the military at the conclusion of hostilities, the site remained a terminus and crossing point for trappers, frontiersmen, and traders. In 1849 Fort Duncan was established two miles upstream, and its proximity caused a rudimentary settlement to spring up at the crossing below the post. In 1850 San Antonio merchant James Campbell opened a trading post there, and he was soon joined by William Leslie Cazneau and his bride, Jane Cazneau. The village, named after the crossing on the Rio Grande, changed from El Paso del Águila to Eagle Pass as the Anglo presence grew. Concurrent with the growth of Eagle Pass below the fort, emigrants bound for the California gold fields (via Mazatlán) established a staging area above the post known as California Camp. The resulting trade and traffic brought a shift in the settlement of Eagle Pass from the old crossing downstream to its present location above the fort. John Twohig, owner of the land, surveyed and laid out a townsite, which he named Eagle Pass. Friedrich W. C. Groos contracted to haul supplies for the military and brought some seventy Mexican families to settle near the fort. A stage line between Eagle Pass and San Antonio was established in 1851. Our Lady of Refuge Catholic Church was constructed in 1852.
The early history of Eagle Pass was often characterized by violence. The settlement and adjoining fort were frequently attacked by the Lipan Apache and Comanche Indians. Piedras Negras, established in 1850 across from Eagle Pass in Mexico, became a haven for fugitive slaves, and both banks of the river were infested with outlaws. In 1855 James H. Callahan crossed into Mexico at Eagle Pass with three companies of volunteer rangers in pursuit of Lipans and Kickapoos. After a fight with Mexican forces on the Escondido, he fell back on Piedras Negras and set the village afire as he crossed back into Eagle Pass. During the Civil War, a party of renegades crossed from Piedras Negras and overran the Confederate garrison at Fort Duncan. The townsmen, fighting from behind a barricade of cotton bales, successfully drove off their assailants. Following federal occupation of Brownsville in 1863, Eagle Pass became an important shipment point for Confederate cotton. After the war the last Confederate force in the field, the Shelby expedition, crossed the Rio Grande at Eagle Pass and in a ceremony buried in the river the last flag to fly over Confederate troops.
Maverick County, which had been formed from Kinney County in 1856, was finally organized in 1871, and Eagle Pass became the county seat. St. Joseph's Academy, a Catholic school for girls, was opened in 1872. By 1875 the population numbered 1,500 and consisted of Anglo-Americans, Germans, and mostly Mexicans. Their principal occupation was mercantile business and stock raising. Following the war years, bands of cattle thieves and fugitives led by John King Fisher dominated Eagle Pass through the 1870s, notwithstanding the multiple interventions of the Texas Rangers. Law and order was restored with the coming of the railroad in the next decade. In 1882 the Galveston, Harrisburg and San Antonio Railway built from Spofford to Eagle Pass, connecting the isolated community to the rest of the country. Rail construction was continued into Mexico at Piedras Negras as the Mexican National Railway, and the community became an important international center. By 1884 Eagle Pass had an estimated population of 2,000, and a new courthouse was erected the following year. An Episcopal church, the first Protestant church in the community, was completed in 1887.
Eagle Pass grew slowly in the early decades of the twentieth century, reaching 2,729 inhabitants in 1900 and 5,765 in 1920. The community served a diverse region of ranches, coal mines and farms. After falling slightly to 5,059 inhabitants in 1930, the population grew to 7,247 in 1950. Irrigated farming techniques strengthened the agricultural economy of the region in the 1930s and 1940s, and Eagle Pass Army Air Field was constructed twelve miles north of Eagle Pass during World War II. From the 1950s to the 1980s the town grew dramatically, reaching 12,094 inhabitants in 1960, 15,364 in 1970 and 21,407 in 1980. Always a town with a large Hispanic majority, Eagle Pass was 94 percent Hispanic in 1980. With the completion of Highway 57, Eagle Pass became a major gateway to Mexico, and the town, along with Piedras Negras, developed a substantial tourist trade. Retailers on both sides of the border served Mexican and American tourists and for years enjoyed a flourishing business. In the late 1960s the city embarked on a "Model Cities Program" to modernize city services. Government grants funded the construction of new water and sewer plants, new schools, and an industrial park. Several manufacturing concerns located in the area in the 1970s and 1980s, and significant oil finds boosted the local economy during those years. In 1982 the devaluation of the peso led to economic depression in Eagle Pass as Mexican shoppers stopped coming to the town. Later in the decade the local economy was given a boost from the establishment of maquiladoras in the area. Five industrial plants were located in Eagle Pass and nineteen in Piedras Negras by 1987. Textile and arms manufacturing were the leading employers. In 1990 the population had dropped a bit to 20,651, but Eagle Pass remained a center for county government, tourism, and varied manufacturing. The population was 22,413 in 2000.