New York State Route 12D

New York State Route 12D
NY 12D highlighted in red and NY 970J in blue
Route information
Auxiliary route of NY 12
Maintained by NYSDOT
Length	11.50 mi[1] (18.51 km)
Existed	1930[2]–present
Major junctions
South end	NY 12 in Boonville
Major intersections	NY 26 at Potters Corners
North end	NY 12 in Lyons Falls
Location
Country	United States
State	New York
Counties	Oneida, Lewis
Highway system
New York Highways Interstate US State Reference Parkways
← NY 12C → NY 12E

New York State Route 12D (NY 12D) is a north–south state highway located in the northern part of New York in the United States. The southern terminus of the route is in the Oneida County village of Boonville, where it intersects NY 12. The northern terminus is at a junction with NY 12 in the Lewis County village of Lyons Falls. NY 46 and NY 294 are also present in the immediate area of the route's southern terminus.

NY 12D was originally assigned as part of the 1930 renumbering of state highways in New York to most of what is now NY 12 between Boonville and Lowville. The alignments of both routes between the two locations were swapped c. 1939, placing NY 12D on its current alignment from Boonville to Potters Corners (in the Town of West Turin) and on NY 26 between Potters Corners and Lowville. The overlap between NY 12D and NY 26 remained in place until the 1970s when NY 12D was realigned onto its current routing between Potters Corners and Lyons Falls, replacing then-New York State Route 337.