Speckle-chested Piculet is resident in a small area along the east slope of the Andes of northern Peru, in the departments of San Martín and Amazonas. Most known localities are in the drainage of the Río Huallaga, but it also has been found at one site in the Utcubamba valley, at tributary of the Río Marañón (unpublished specimens in the Museum of Vertebrate Zoology). The northernmost known locality is on the east side of Abra Patricia, in the Río Mayo drainage northwest of Moyobamba (Parker and Parker 1982), and the southernmost locality is at La Rivera (06º52' S; Samamé and Fjeldså 1999).
The areas of humid montane forest that drain into the Río Marañón north and northwest of Moyobamba are all but unknown; it is possible that the distribution of Speckle-chested Piculet extends into this region. Also very poorly known are the regions between La Rivera and the relatively well known Cordillera Carpish in the department of Huánuco; it is possible that Speckle-chested Piculet also occurs farther south than currently is known.
The elevational distribution of the Speckle-chested Piculet is 1000-2300 m (Hornbuckle 1999).