Occupying a relatively large pre-Amazonian range across the interior of central South America, the Large-billed Antwren is most easily identified in female plumage, which is characterized by a bright orange head, becoming slightly paler over the underparts. In contrast, the male’s mix of black, white, and gray is pretty much typical of the vast majority of Herpsilochmus antwrens. The Large-billed Antwren is distributed from northeast Brazil south and west to northeast Bolivia, and is found in gallery forest, semi-deciduous and deciduous woodland, and in palm groves. It frequently occupies relatively small woodlots within cerrado formations, and also occurs on river islands. Throughout its range, the Large-billed Antwren is somewhat unusual amongst its genus in that it regularly descends to the understory to feed, although the species also occurs to canopy levels. Like congenerics, it regularly joins mixed-species flocks, but is usually found in pairs.