The Alagoas antwren is found in subtropical or tropical moist lowland in a 230 km2 range at 500–790 m elevation in Brazil, across Murici, Mata do Estado, and Serra do Urubu.
The Alagoas antwren is considered critically endangered, with a population estimated at fewer than 30 individuals as of 2014. Additionally, this population is thought to be decreasing due to farming, ranching, logging, and urban development within its range. As of 2018, there are concerns that a lack of recent records outside of Murici suggests that the population outside of it has severely decreased if not disappeared.
