- Western Terminus:
- Middle Country Road (NY 25) in Smithtown
- Eastern Terminus:
- Montauk Highway (CR 80) in Brookhaven
- 16.60 miles
CR 16 is an east/west route that runs diagonally through central Suffolk. It begins at Middle Country Road (NY 25) in Smithtown and runs south as Terry Road for a short distance. It then runs east as Smithtown Boulevard, Lake Shore Road, and Portion Road, about a mile to the north of the Long Island Expressway (I-495). There is grade-separated interchange with Nicolls Road (CR 97). Just to the east of this interchange, CR 16 changes names again to become Horseblock Road. East of NY 112, Horseblock Road cuts to the southeast, crossing the Long Island Expressway (I-495) and Sunrise Highway (NY 27). It ends at Montauk Highway (CR 80) in Brookhaven.