The treaty established the Louisiana-Texas border.
I not 100% but I think it is Spain.
After the Guadalupe-Hidalgo treaty in 1848.
The Red River
Before the Adams-Onís Treaty was signed in 1819, the eastern boundary between Texas and Louisiana was generally defined by the Sabine River. This boundary was established in the 1819 treaty, which aimed to resolve territorial disputes between the United States and Spain. The treaty ultimately defined the border more clearly, but prior to it, the exact boundary was often ambiguous and contested.
It made the Sabine river the eastern border It also made the top
Established the thirty-first parallel as the border between the United States and Spanish West Florida.
It was resolved when the two countries made a treaty.
Washington's borders were established through a combination of territorial agreements and legislative actions. Originally part of the Oregon Territory, it was separated in 1853 to create the Washington Territory. The northern border was defined by the 1846 Oregon Treaty with Britain, which established the 49th parallel as the boundary. The eastern and southern borders were shaped by subsequent treaties and statehood legislation, culminating in Washington becoming the 42nd state in 1889.
The Rio Grande was designated as the U.S.-Mexican border in the Treaty of Guadalupe Hidalgo, which was signed in 1848. This treaty ended the Mexican-American War and established the boundary between the two nations, extending from the Gulf of Mexico to the Pacific Ocean. The Rio Grande's designation as the border has had lasting implications for both countries' relations and territorial claims.
Origan Treaty
The border chosen by President Polk was the Rio Grande. After the Mexico- American War that ended in 1848, the Rio Grande was established as the border between Mexico and the United States as agreed upon in the Treaty of Guadalupe Hidalgo.