Preakness is the section of Wayne that Valley Road runs through. The area, whose name comes from a Native American word meaning “quail woods”, was once known for horse farming; the horse Preakness, a champion in the early 1870s for whom Baltimore’s Preakness Stakes is named, was raised there. Old-timers say the section and street are properly pronounced PRAKE-ness or PRECK-ness, but most folks say PREEK-ness, as the horse and stakes race are known.
Given the reputation of the number 666, it almost seems appropriate that the highway number was assigned to a hilly, winding, somewhat dangerous road. Motorists on Preakness Avenue are advised: The speed limit is there for a reason. Drive safely.
The NJDOT straight-line diagram of this highway runs from east to west (coming out of Paterson), but I have reversed it for consistency.
| Mile | Street Name | Feature (West to East) |
| 0.00 | CR 666 BEGINS, Wayne Twp | |
| 0.00 | Preakness Ave | Valley Rd, CR 681 |
| 0.27 | Preakness Ave | Singac Brook {bridge} |
| 0.30 | Preakness Ave | Branch Singac Brook {bridge} |
| 1.09 | Preakness Ave | (Oldham Rd, CR 685) |
| 1.41 | Preakness Ave | Naaktpunkt Brook {bridge} |
| 1.58 | Entering Totowa Boro | |
| 1.65 | Entering (Haledon Boro) [Totowa Boro] | |
| 1.85 | Entering Paterson City | |
| 2.11 | Preakness Ave | Chamberlain Ave {signal} |
| 2.16 | Preakness Ave | Oldham Brook {bridge} |
| 2.28 | Preakness Ave | Crosby Ave {signal} |
| 2.44 | Preakness Ave | Union Ave, CR 646 {signal} |
| 2.62 | Preakness Ave | Totowa Ave, [CR 640] {signal} |
| 2.86 | CR 666 turns left onto Front St | |
| 3.07 | CR 666 turns right onto Wayne Ave | |
| 3.10 | Wayne Ave | Passaic River {bridge} |
| 3.13 | Wayne Ave | (Spruce St) [McBride Ave], CR 639 {signal} |
| 3.13 | CR 666 ENDS, Paterson City | |