The 1966 Derrick was held on August 15..
The 1966 Derrick was again directed by Tom Cox who took the event into the goldfields forests around Maryborough and Dunnolly, areas that the event would continue to use for the next seven years.
The event was won narrowly by Harry Firth and Graham Hoinville in a Cortina, from Tony Roberts and Peter Haas in a Holden.
| Place | Driver | Navigator | Car | Points |
|---|---|---|---|---|
| 1 | Harry Firth | Graham Hoinville | Cortina GT | 26 |
| 2 | Tony Roberts | Peter Haas | Holden X2 | 27 |
| 3 | Reg Lunn | Geoff Thomas | Holden X2 | 31 |
| 4 | Ray Christie | Martin Hartigan | VW 1600 | 51 |
| 5 | Ian Vaughan | Roger Vaughan | Cortina GT | 106 |
| 6 | Bob Watson | Jim McAUliffe | Holden X2 |
The event started around Lancefield and headed generally north west to Maryborough, then to the north around Dunnolly and Kingower, before heading back east and south to the finish near Kilmore.
Route Instructions (missing page 2)
Plot of route (incomplete)
None available.