CR 16 begins as Terry Road at an intersection with NY 25 in Village of the Branch.

Several blocks south of NY 347, CR 16 joins Smithtown Boulevard, while Terry Road continues to run south as a road maintained by the Town of Smithtown, and crosses the Islip town line into Ronkonkoma.

It is unknown how this section connected to the present terminus of Terry Road at NY 25 while traversing the surrounding terrain.

The east end of this section near Schoolhouse Road has suffered such excessive flooding that it was closed by Suffolk County and turned over to the Parks Department, while the rest of it was sold to a local night club on the lake and transformed into part of the parking lot.

Suffolk County is currently planning to widen the rest of the road to four lanes.

The connection between the two streets are cut off by a shopping center on the north side of NY 25 between Mark Tree and Eastwood Road.

East Lake Shore Terrace Drive and Portion Road used to be part of CR 19 from the Smithtown–Brookhaven Town Line to Waverly Avenue in Farmingville.

The construction of Sunrise Highway in 1957 lead to the realignment of Horseblock Road west of its original eastern terminus with South Country Road (former Montauk Highway) in South Haven.