New York State Route 40

New York State Route 40
Map of eastern New York with NY 40 highlighted in red
Route information
Maintained by NYSDOT, Rensselaer County and the city of Troy
Length:	54.67 mi (87.98 km)
Existed:	1930 – present
Major junctions
South end:	NY 7 in Troy
	NY 29 near Greenwich
North end:	NY 22 in Granville
Location
Counties:	Rensselaer, Washington
Highway system
New York Highways Interstate U.S. State Reference Parkways ← NY 39 NY 41 →

New York State Route 40 (NY 40) is a north–south state highway in eastern New York in the United States. It is 54.67 miles (87.98 km) long and runs from NY 7 in the city of Troy north to NY 22 in the town of Granville. NY 40 also passes through the villages of Schaghticoke and Argyle and enters the vicinity of the village of Greenwich. It intersects three east–west highways of note: NY 67 just outside Schaghticoke, NY 29 west of Greenwich, and NY 149 in the hamlet of Hartford. Incidentally, NY 40 has overlaps with all three routes.

NY 40 originally extended south to East Greenbush and north to when it was assigned as part of the 1930 renumbering of state highways in New York. The route was truncated south to NY 149 in Hartford in the early 1940s and north to U.S. Route 4 in North Greenbush in the late 1950s. It was re-extended northward to its current northern terminus in the 1960s, but also truncated northward to its current southern terminus in the early 1970s. In 1980, ownership and maintenance of the portion of NY 40 south of NY 142 and outside of Troy was transferred from the state of New York to Rensselaer County as part of a highway maintenance swap. This section of the route is co-designated and co-signed as County Route 145 (CR 145) and has no reference markers.