[1] It is a very short route, running for only 11.0 kilometres (6.8 mi), with its only community, Springdale, as its terminus.

Route 390 begins in a rural area at an intersection with Route 1 (Trans-Canada Highway) and it heads northeast to cross Indian Brook and have an intersection with Route 391 (Harry's Harbour Road).

Springdale Airport can be accessed from the highways southern terminus by traveling 1 kilometre east on Route 1.

The highway heads northeast through wooded areas for a few kilometres, paralleling the Indian Brook, to enter the Springdale town limits and have an intersection with Route 392 (Beachside Road).

Route 390 passes through some business districts and neighbourhoods, where it passes by George Huxter Memorial Park, before entering downtown and coming to an end at a Y-Intersection with Main Street in downtown.