hill
崗 centers on a hill or elevated landform, often used in names or compounds referring to a mound or ridge.
崗 combines 山 (mountain) with 岡 (hill), reinforcing the idea of a hill or ridge. The exact historical development is uncertain, but it likely served as a reinforced semantic compound.
A mountain 山 sits on top of a hill 岡, making the whole character a doubly elevated hill.
For コウ, picture a hill so high it touches the sky, and a crow (コウ) perches on top: crow -> コウ, and the crow surveys the hill.