The Harplage is a hill range, up to 290 metres high, located west-northwest of the Harz in the southeast of the German state of Lower Saxony.
The forested Harplage is located in the district of Hildesheim in the southwestern part of the Innerste Uplands, a northeastern range of the Lower Saxon Hills and borders on the Ambergau to the west.
A few kilometres away is the ridge of Hainberg northeast of the Nette valley and somewhat southeast of this river are the northwestern foothills of the Harz.
A number of forest tracks and hiking trails cross the unpopulated ridge, but there are no roads through the hills.
Amongst the attractions of the Harplage are the Dillsgraben sinkhole, which by the castle of Dillsburg on its eastern edge northwest of Königsdahlum at an elevation of 179 metres.