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New York State Route 100A

State highway in Westchester New York, US

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionMay 8, 2025
Entity authorityQ2486202 ↗
Source-derived summary

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.

Route description

NY 100A begins at an intersection with NY 100 (Central Park Avenue) in the town of Greenburgh, a short distance north of Hartsdale. NY 100A winds northwest through the hills of Greenburgh as West Hartsdale Avenue, passing multiple residences on its way up. Just after Woods End Lane, the route turns northward through Greenburgh, passing Ridge Road County Park and the Metropolis Country Club before reaching a junction with NY 100B (Dobbs Ferry Road). At this junction, NY 100A changes monikers to Knollwood Road, winding northward through Greenburgh into a junction with NY 119 as it crosses into the village of Elmsford.

After NY 119, NY 100A passes Yosemite Park and enters exit 4 off the Cross Westchester Expressway (I-287). NY 100A continues northeast through Elmsford, running along the southeastern edge of the Knollwood Country Club and passing an entrance to Westchester Community College. After passing the entrance, the route winds northward through Greenburgh, passing multiple residences before reaching a junction with NY 100 (Grasslands Road) and NY 100C (Grasslands Road) just east of the Sprain Brook Parkway.

Editorial summary

The public source identifies “New York State Route 100A” as state highway in Westchester New York, US. This brief keeps that definition visible, then builds a research path around York, State and Route.

Editorial reviewA practical starting point whose main value is the path it opens into stronger specialist and primary sources. The current 245-word lead offers orientation but no explicit four-digit date, so chronology should not be assumed. The linked authority record independently contributes the date 1930. Its value is orientation rather than verdict, with York, State and Route providing the first useful test.
Editorial analysis

Why this record matters

A short description can identify a subject without explaining its stakes. For “New York State Route 100A”, the useful work is to connect “state highway in Westchester New York, US” to the records capable of establishing context and consequence.

Evidence profile

Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated May 8, 2025. The linked authority identifier is Q2486202. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank.

Critical limits

Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.

How to read it

Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.

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  2. Expand the search: follow New York State Route 100A primary sources, New York State Route 100A archive and York research across catalogues and specialist indexes.
  3. Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.

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Source & attribution

This entry incorporates text from “New York State Route 100A” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.