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
American River of the Lakes) which may or may not have been an error, as in those times the area of the Central Valley surrounding the American River was home to vast marshes, which would have given the river the appearance of a series of lakes. During the 1820s, Jedediah Smith led an expedition to the American River with the goal of finding a safe route across the Sierra Nevada. After a failed attempt to cross the mountains via the South Fork of the American River, Smith's group managed to cross via Ebbetts Pass on the headwaters of the Stanislaus River, becoming