The ancient Sa Huỳnh culture inhabited what is now Quảng Ngãi. Remains of it were found in Sa Huỳnh, Đức Phổ district. Within Champa, the region that is now Quảng Ngãi was less significant than Quang Nam Province and Vijaya. There are only a few Cham remains in the province. The area became part of Vietnam along with Vijaya (Bình Định province) in 1471. In the early 19th century the Long Wall of Quảng Ngãi was constructed in the province. It improved security among the Vietnamese and H're people and facilitated trade.