The city of Corpus Christi lies on the Texas coast along the sediment-laden bay of the same name. Corpus Christi, with a population of more than 235 000, is a major petroleum and natural gas production center. Heavy industry abounds in the area, with oil refineries, smelting plants, chemical works, and food processing establishments scattered throughout the city and its outlying regions. The city also supports a major fishing industry. Tourist and recreational resorts have become a major business on North Padre Island, east of the city on the Gulf of Mexico. Padre Island, which begins north of Corpus Christi near Port Aransas and parallels the Texas coast southward to near the United States-Mexico border, is the longest barrier island in the United States. Agricultural field patterns are visible west and northwest of Corpus Christi. West of the city, the Nueces River enters Nueces Bay, which, in turn, empties into Corpus Christi Bay. A dredged shipping channel is visible (dark turquoise water) traversing Corpus Christi Bay to its mouth near Port Aransas. Interstate Highway 37 can be seen running through Corpus Christi, crossing Laguna Madre, and terminating on North Padre Island.