zone agreement on November 6, 1806, negotiated by Gen. James Wilkinson and Lt. Col. Simón de Herrera, to establish a neutral territory on both sides of the river. Neither country would put military troops or civil police there. The indefinite boundary was resolved by the Adams-Onis Treaty of 1819, which established the Sabine River as the boundary from the Gulf to the 32nd parallel. The Spanish delay in the ratification of the treaty, and Mexico gaining independence in 1821, reignited the boundary dispute. The United States, at the insistence of Anthony Butler, claimed for a while that the names of the Sabine and Neches had been reversed, thus they claimed that the treaty established the boundary at the Neches. The first Anglo-American settlers began arriving in the region in the 1820s, soon outnumbering the Mexicans by ten to one. After the independence of the Republic of Texas from Mexico in 1836, the boundary between the U.S. and Texas was firmly established at the Sabine in accordance with the Adams-Onis Treaty. The river served as the western boundary of the United States until it annexed Texas in 1845. Riverboats In 1843, Capt. John Clemmons made the first trip up the Sabine in the steamboat Sabine. Steamboats carried passengers, as well as commodities such as cotton, from as far north as Logansport, Louisiana, down to Sabine Pass. The pirate Jean Lafitte made many trips up the Sabine and reportedly started the colony of Shacklefoot on the Texas side of the Sabine River, south of Carter's ferry up Bayou Patroon. During the American Civil War, on September 8, 1863, a small Confederate force thwarted a Union invasion of Texas at the Second Battle of Sabine Pass, fought at the mouth of the river. In the late 19th and early 20th centuries, the middle course of the river was an area of widespread logging. The discovery of petroleum at nearby Spindletop led to the river basin becoming the scene of widespread oil drilling. The lower river became heavily industrialized, developed with many oil refineries and chemical plants. Such alteration to the wetlands resulted in a degradation of the water quality. Since the late 20th century, there have been federal, state, and local efforts to restore the quality of the river. In addition, draining of wetlands and dredging of bayous has caused decline in the acreage of wetlands, resulting in coastal erosion, and making the