Sigal was a city of the Helmund valley in south-west Afghanistan (ancient Sacastene).
The presence of the Sakas in Sakastan in the 1st century BCE, with their capital at Sigal, is mentioned by Isidore of Charax in his "Parthian stations". He explained that they were bordered at that time by Greek cities to the east (Alexandria of the Caucasus and Alexandria of the Arachosians), and the Parthian-controlled territory of Arachosia to the south: