Somotillo is a town and a municipality in the Chinandega department of Nicaragua. According to the Instituto Nicaragüense de Estudios Territ…Somotillo is a town and a municipality in the Chinandega department of Nicaragua. According to the Instituto Nicaragüense de Estudios Territoriales, the municipality of Somotillo measures 724.71 km² and lies approximately 41 meters above sea level. Physiographically, most of the municipality lies north and east of the Nicaraguan Depression or Graben in the western foothills of the central cordillera of the country. The area drains into the Pacific, largely through the Estero Real. The town of Somotillo is located on the northern bank of the Rio Gallo, also known as the Rio Grande. A seasonal stream known as the Tecomapa runs north of the town.