Brownish elaenia the Xingu River in the south of Pará state, North Region, Brazil; it ranges upstream on the Xingu for 700 km, then a tributary to the west of the Xingu, the Rio Iriri, for another 700 km. The next upstream tributary for the bird's range, is the Madeira River in the Amazon Basin's southwest, Amazonas state. The range proceeds 2400 km upstream into the headwaters of the Madeira in northern Bolivia. To the west the brownish elaenia's range continues as the Amazon River becomes the Marañón River and proceeds to the headwaters in northern Peru; this is also along the
Red River of the South and Spain. That boundary continued to be recognized when Mexico gained its independence from Spain, then again when Texas became independent from Mexico. It remained so until the United States Congress consented to the Red River Boundary Compact adopted by the states of Oklahoma and Texas, which set the jurisdictional boundary between Texas and Oklahoma at the vegetation line on the south bank, but left title of adjacent property owners at the south bank. The Red River Campaign (March–May 1864) was fought along the Red River Valley in Louisiana during the American Civil War. It was a failed attempt by