Gladewater is a city in Gregg and Upshur counties in the U.S. state of Texas. The population was 6,441 at the 2010 census. U.S. Route 80 traverses the city.The town is probably most famous as a base during Elvis Presley's early career, and also as the town in which Johnny Cash wrote "I Walk the Line". In the early 20th century, Gladewater was an oil boom town. Gladewater is known as the "Antique Capital of East Texas" with its Main Street downtown antique district.