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New York State Route 100
Map of Southeastern New York with NY 100 highlighted in red
Route information
Maintained byNYSDOT andWestchester County
Length	33.27 mi[1] (53.54 km)
Existed	1930[2]–present
Major junctions
South end	I-87 /New York Thruway /Cross County Parkway inYonkers
Major intersections	Sprain Brook Parkway in Yonkers andHawthorne NY 119 /Bronx River Parkway inWhite Plains I-287 in White Plains NY 9A /NY 141 /Saw Mill River Parkway in Hawthorne Taconic State Parkway inMount Pleasant NY 9A inBriarcliff Manor NY 133 /Taconic State Parkway inMillwood NY 35 inSomers
North end	US 202 in Somers
Location
Country	United States
State	New York
Counties	Westchester
Highway system
New York Highways Interstate US State Reference Parkways
←NY 99 →NY 100A

New York State Route 100 (NY 100) is a major north–south state highway inWestchester County, New York, in the United States. It begins parallel toInterstate 87 (I-87) at a junction with theCross County Parkway in the city ofYonkers and runs through most of the length of the county up toU.S. Route 202 (US 202) in the town ofSomers. NY 100 was designated as part of the1930 renumbering of state highways in New York. Prior to becoming a state road, various sections of NY 100 were part of several important early roads in the county.

NY 100 begins in the city ofYonkers as Central Park Avenue (almost always just called "Central Avenue") at exit 4 of theNew York State Thruway (I-87).^[1] This portion of Central Avenue is maintained by Westchester County asCounty Route 47II (CR 47II), anunsigned reference route.^[3] Central Avenue continues south as a service road for I-87 untilThe Bronx, where it splits from I-87 shortly after entering the city, and becomes Jerome Avenue, a major surface road in the West Bronx. NY 100 diverges from I-87 just north of exit 5 and heads northeast, crossing over theSprain Brook Parkway about 0.6-mile (1.0 km) beyond the split. Central Avenue has an interchange with Tuckahoe Road shortly after theSprain Brook Parkway. The road continues through Yonkers in the area between theGrassy Sprain Reservoir and theBronx River, with many retail establishments lining both sides. At the northernmost part of the city, Central Avenue intersects Fort Hill Road, which leads to Jackson Avenue and the northboundSprain Brook Parkway. Central Avenue continues out of the city of Yonkers into the Edgemont/Greenville section of the town of Greenburgh. The only noteworthy intersection in this area is with Ardsley Road, an east-west road that goes straight across most of south-central Westchester. NY 100 runs through the hamlet ofHartsdale, about two miles (3 km) north of the city line, and where the bypass routeNY 100A (Hartsdale Avenue) begins. Hartsdale Avenue also continues east of the intersection into the village of Hartsdale without a route designation. Central Avenue then enters the city limits ofWhite Plains, where the road ends atNY 119 (Tarrytown Road). Within White Plains, the road is county-maintained with unsigned designations of CR 99 and CR 90.^[3][4]

NY 100 north follows NY 119 west for a 0.5-mile (0.8 km) overlap through the western reaches ofWhite Plains. Access toI-287 (the Cross Westchester Expressway) and theBronx River Parkway can be made in the vicinity of the 100/119 overlap. NY 100 then splits off to the north using Hillside Avenue and Grasslands Road as it goes around the perimeter ofWestchester Community College. At a four-way intersection between Grasslands Road, Knollwood Road, and Bradhurst Avenue, NY 100 meets with the north end ofNY 100A (Knollwood Road) and the east end ofNY 100C. NY 100 makes a right-hand turn to follow Bradhurst Avenue north from the junction while Grasslands Road continues west as NY 100C. Bradhurst Avenue leads into the hamlet ofHawthorne within the town ofMount Pleasant, crossing over theSprain Brook Parkway along the way. NY 100 subsequently shifts onto Saw Mill River Road (NY 9A), after using a brief section ofNY 141 (Broadway). From this junction, the roadway (carrying 9A and 100) is a four-laneexpressway as it continues north alongside theTaconic State Parkway. It has an interchange withNY 117 (Bedford Road) about 1.1 miles (1.8 km) north of the 9A/100 merge, with all exits and entrances on the left. 9A and 100 then enter the eastern edge of the village ofBriarcliff Manor.^[4]

NY 100 then branches off on its own again in Briarcliff Manor, with NY 9A continuing north as theBriarcliff–Peekskill Parkway and NY 100 continuing northeast on Saw Mill River Road, now atwo-lane expressway, which roughly followsNew York Central's oldPutnam Division railroad. Many of the railroad's old stations can still be found along the highway. NY 100 passes throughNew Castle before meetingNY 133 and theTaconic State Parkway in the hamlet ofMillwood, where it becomes a two-lane surface road. NY 100 continues into the town ofYorktown, passing by the hamlet ofKitchawan. NY 100 then crosses theCroton Reservoir on Pines Bridge. After crossing the reservoir,NY 118 splits off to the west on Saw Mill River Road, while NY 100 continues northeast, now called Somerstown Turnpike.^[4]

Somerstown Turnpike continues into the town ofSomers, passing by some of the last remaining rural areas in Westchester County, includingMuscoot Farm, a county owned early-1900s interpretive farm. North of the farm NY 100 intersects withNY 35 in the hamlet ofWhitehall Corners, site of a PepsiCo complex. In its northern extremes, NY 100 roughly parallels the Croton Reservoir on the north side before meeting up withUS 202 in the hamlet ofSomers, where it ends opposite theElephant Hotel.^[4]

The southernmost section of NY 100, known as "Central Avenue", appeared in maps by 1888. It was constructed as aplank road in 1874 connectingMacombs Dam Bridge (then known as Central Bridge) to Westchester County. The road continues south into theBronx asJerome Avenue, which was originally also called Central Avenue.^[5]

NY-100 uses Saw Mill River Road fromHawthorne until it splits from NY 100 in the Town ofYorktown to follow NY 118. The Saw Mill River Road is an early colonial road connecting many different hamlets and villages in Westchester County.^[6] It follows along the path of various rivers and brooks, the most notable of which being the road's namesake, theSaw Mill River, as it winds its way to the north of the county. The road is now used as parts of several state routes, includingNY 9A, NY 100, andNY 118. The segment used by NY 100 mostly follows thePocantico River.

The northernmost section of NY 100 runs along a part of the "Croton Turnpike", an early private toll road that was chartered in 1807.^[7] The Croton Turnpike connects the village ofOssining (then called Sing Sing) to the hamlet ofSomers viaKitchawan. The road was made free in 1849.^[8] The Saw Mill River Road was rerouted to overlap the Croton Turnpike as it navigates around and across the Croton Reservoir, which was constructed between 1837 and 1842.^[9]

In 1908, theNew York State Legislature created Route 2, an unsignedlegislative route extending from theNew York City line atYonkers to theColumbia County village ofValatie. Route 2 followed Central Avenue (now NY 100) north through Yonkers toHartsdale, where it veered west to bypassWhite Plains on modernNY 100A,NY 100B, andNY 119. It rejoined what is now NY 100 at the junction of Tarrytown Road (NY 119) and Hillside Avenue and followed it north along Hillside Avenue and Grasslands Road to the modern junction of NY 100, NY 100A, andNY 100C, at which point Route 2 continued west toward theHudson River on current NY 100C.^[10][11]

NY 100 was first designated in the1930 renumbering of state highways in New York, when many of the state roads in Westchester County were first publicly posted with route numbers. Originally, it went north from the Croton Reservoir toUS 6 (nowNY 6N) inMahopac Falls on what is now NY 118, Baldwin Place Road, and Myrtle Avenue. Also assigned at this time was NY 118, which began adjacent to the Croton Reservoir at NY 100 and proceeded northeast along the Croton Turnpike toNY 22 inCroton Falls via modern NY 100 andUS 202.^[2][12] The alignments of NY 100 and NY 118 north of the Croton Reservoir were swappedc. 1939, placing NY 118 on the more westerly alignment and NY 100 on the Croton Turnpike between the reservoir and Croton Falls.[13]^[14]

In December 1934, at the insistence of the Automobile Club of New York, several numbered routes were extended and signed withinNew York City, with NY 100 being one of these routes. NY 100 was extended south from the Yonkers line in the Bronx alongJerome Avenue to theGrand Concourse. NY 100 crossed into Manhattan viaEast 149th Street and the145th Street Bridge. In Manhattan, NY 100 continued south alongLenox Avenue,110th Street,Fifth Avenue,96th Street, andPark Avenue, ending atHouston Street (NY 1A). South ofFordham Road, NY 100 was overlapped withNY 22 all the way to Houston Street.^[15] The NY 100 designation was removed fromNew York City following the opening of theMajor Deegan Expressway in 1956.^[16]

In 1934, US 202 was designated and overlapped with NY 118 (later NY 100) fromSomers to Croton Falls.^[17] The overlap between NY 100 and US 202 lasted as late as 1990.^[18] NY 100 was cut back to end at US 202 in Somers by 2004.^[19] The south end of NY 100 had been at the New York City line since 1956;^[16] however, as of 2007,NYSDOT recognizes theCross County Parkway underpass as the official southern terminus of NY 100.^[20]

In April 1956, the Westchester County Planning Commission recommended that a new expressway should be built along the current NY 100 north of White Plains. The road was to be an extension of the Central Corridor Expressway, which was proposed asNY 125. This 21-mile (34 km) extension was stretch toPutnam County.^[21] The area was a high-priority corridor, stretching from theCross Westchester Expressway (I-287) to the proposedNorthern Westchester Expressway (NY 35). North of NY 35, the area was a medium-priority corridor, ending atUS 6 in Mahopac. This plan never materialized andInterstate 684 along the NY 22 corridor was built instead.^[21]

• NY 100A (4.21 miles or 6.78 kilometres) is a bypass route of NY 100 that lets motorists avoid the frequently congested stretch of NY-100 inWhite Plains.^[1] NY 100A connects toInterstate 287 and goes near the NY 100B entrance to theSprain Brook Parkway. It was assigned as part of the1930 renumbering of state highways in New York.^[2]
• NY 100B (2.88 miles or 4.63 kilometres) is a spur offNY 119. Although the route does not intersect NY 100, it meets NY 100A and terminates at NY 119 roughly 200 yards (180 m) from where NY 119 meets NY 100 andI-287.^[1] It connects to theSprain Brook Parkway. The route was assigned in the late 1930s.^[22][23]
• NY 100C (1.24 miles or 2.00 kilometres) is a spur off NY 100 inEastview.^[1] It connects to theSaw Mill Parkway at its western terminus and theSprain Brook Parkway near its intersection with NY 100 and NY 100A. It was assigned in the late 1930s.^[22][23]

The entire route is inWestchester County.

Location	mi[1]	km	Destinations	Notes
Yonkers	0.00	0.00	Central Park Avenue	Continuation south
			Cross County Parkway toBronx River Parkway	Exit 4N on Cross County Parkway
	0.10	0.16	I-87 south (New York Thruway) –New York City	Southbound exit and northbound entrance; exit 5 on I-87 / Thruway
			Midland Avenue	Interchange
	0.20	0.32	I-87 north /New York Thruway north –Tappan Zee Bridge,Albany	Northbound exit and southbound entrance; exit 4 on I-87 / Thruway
	1.00– 1.11	1.61– 1.79	Palmer Road	Interchange
			Sprain Brook Parkway	Interchange; no northbound access to Sprain Brook Parkway south
	1.72	2.77	Tuckahoe Road	Interchange
Town of Greenburgh	4.72	7.60	Ardsley Road –Ardsley,Scarsdale,Scarsdale Station	Hamlet ofEdgemont (Greenville)
	6.89	11.09	NY 100A north –Hartsdale,Scarsdale,Hartsdale Station	Southern terminus of NY 100A; hamlet ofHartsdale
White Plains	8.61	13.86	NY 119 east /Bronx River Parkway –White Plains,Scarsdale,Valhalla,White Plains Station	Access to Bronx Parkway via Central Avenue; southern end of NY 100 concurrency; exit 22 on Bronx Parkway
			I-287	Northbound exit and southbound entrance; exit 5 on I-287; formerI-487
	9.10	14.65	NY 119 west –Elmsford	Northern end of NY 119 concurrency
Greenburgh–Mount Pleasant town line	12.26	19.73	NY 100A south /NY 100C west toSprain Brook Parkway	Northern terminus of NY 100A; eastern terminus of NY 100C
Town of Mount Pleasant	13.60	21.89	Sprain Brook Parkway south –New York City	Access via Hospital Road
			Sprain Brook Parkway toTaconic State Parkway north /Saw Mill River Parkway north –New York City,Albany	Interchange
	14.73	23.71	ToNY 141 north	No southbound exit; access via Bradhurst Avenue
	14.85	23.90	NY 141 north toTaconic State Parkway south –Hawthorne	Southern end of NY 141 concurrency; southbound exit and northbound entrance; hamlet ofHawthorne
	15.02	24.17	Southern end of limited-access section
			NY 9A south –Elmsford NY 141 ends	Southern end of NY 9A concurrency; northern terminus of NY 141
	15.12	24.33	Saw Mill River Parkway south –New York City,Yonkers	Southbound exit only
	16.15	25.99	NY 117 –Sleepy Hollow,Pleasantville	Left exit and entrance
	16.85	27.12	Taconic State Parkway south –New York City	Southbound exit and northbound entrance; exit 5 on Taconic State Parkway
Briarcliff Manor	17.85	28.73	Pleasantville Road east	Northbound exit and entrance
			Pleasantville Road west	Southbound exit and entrance
	18.13	29.18	NY 9A north –Peekskill,Bear Mountain Bridge	Northern end of NY 9A concurrency; former routing of NY 100
Town of New Castle	20.71	33.33	Northern end of limited-access section
	20.71– 20.85	33.33– 33.55	NY 133 west /Taconic State Parkway –Ossining,New York City,Albany	Southern end of NY 133 concurrency; exit 8 on Taconic State Parkway
	21.10	33.96	NY 133 east –Chappaqua,Mount Kisco	Northern end of NY 133 concurrency
	21.56	34.70	NY 120 south –Chappaqua,Mount Kisco	Northern terminus of NY 120; hamlet ofMillwood
Town of Yorktown	23.23	37.39	NY 134 west –Ossining	Eastern terminus of NY 134
Croton Reservoir			Pines Bridge
Town of Yorktown	24.94	40.14	NY 118 north –Yorktown Heights	Southern terminus of NY 118; formerNY 129
Town of Somers	29.30	47.15	NY 35 –Yorktown Heights,Katonah,Katonah Station	Hamlet ofWhitehall Corners
	29.88	48.09	NY 139 north –Lincolndale	Southern terminus of NY 139
	32.35	52.06	NY 138 east –Goldens Bridge,Goldens Bridge Station	Western terminus of NY 138
	33.27	53.54	US 202 –Brewster,Yorktown,Purdy’s Station	Northern terminus; hamlet of Somers
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Incomplete access

• List of county routes in Westchester County, New York

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