 New York State Route 100A | ||||
|---|---|---|---|---|
 Map of Westchester County in southeastern New York with NY 100A highlighted in red | ||||
| Route information | ||||
| Auxiliary route of NY 100 | ||||
| Maintained by NYSDOT | ||||
| Length | 4.21 mi[1] (6.78 km) | |||
| Existed | 1930[citation needed]–present | |||
| Major junctions | ||||
| South end |  NY 100 in Hartsdale | |||
 I-287 in Elmsford | ||||
| North end |   NY 100 / NY 100C / Sprain Brook Parkway in Greenburgh | |||
| Location | ||||
| Country | United States | |||
| State | New York | |||
| Counties | Westchester | |||
| Highway system | ||||
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New York State Route 100A (NY 100A) is a 4.21-mile (6.78 km) loop route of NY 100 in Westchester County, New York, in the United States. It follows West Hartsdale Avenue and Knollwood Road in the town of Greenburgh. The route starts in the hamlet of Hartsdale and ends in the community of Grasslands at the boundary between the towns of Greenburgh and Mount Pleasant.