It starts at a mini-roundabout on the B519 in the centre of Highgate Village and heads north along Southwood Lane before reaching the A1 at a set of traffic lights. Northbound B550 traffic can only continue along the B550 but southbound traffic can turn left onto the London-bound A1.
Continuing ahead the B550 passes between Highgate Wood and Queen's Wood before reaching a roundabout by St James's church in Muswell Hill. The A504 is met here and the there is a multiplex along Muswell Hill Broadway to the next roundabout where the B550 regains its number, although the street name remains the same. After a short section of dual carriageway to aid the junction with the B106 the B550 reaches a diamond GSJ with the A406 North Circular Road.
After passing Coppett's Wood the B550 reaches traffic lights on the A1003 at Colney Hatch. This is the original northern end of the road but it now continues across to pass the North Middlesex Golf Course into Whetstone, where it ends at a T-junction on the A1000.