Finding · May 29, 2026 · Block-by-block primary source
The Library of Congress holds the Sanborn fire-insurance map series for Brooklyn — block-by-block atlases drawn for insurance underwriters with every building's footprint, construction material, number of stories, and use individually transcribed. Identifying which of the sixteen Brooklyn volumes covered our Windsor Place took five wrong tries (Brooklyn had at least four different Windsor Place streets in the early twentieth century — see the research/sanborn-search-notes.md log). It is in Vol 6, 1906, Sheet 65.
The Sanborn sheet covers Windsor Place from address 1 through 129 — essentially the entire street. Sixty-three buildings are individually drawn and labeled.
One Windsor Place building stands out — the Sanborn sheet identifies it as the “Home for the Aged Little Sisters of the Poor.”Gemini's transcription describes it as a complex of 1-, 2-, and 4-story brick sections, with a laundry with stone floors, a wagon house, and what the Sanborn enumerator labeled explicitly as “a room for corpses.” The main building has a basement.
The Little Sisters of the Poor are a Roman Catholic religious order founded by Saint Jeanne Jugan in 1839 in Saint-Servan, France. The order's mission is to care for the elderly poor. By 1906 they ran homes across the United States; the Windsor Place location is one of the oldest continuously-operating Catholic institutional buildings on the block. The 1888 New York Age coverage of James Shells buying property on East 4th Street, Windsor Terrace (in our Lives finding) implies an established religious-institutional infrastructure was already in place; the Sanborn confirms it for Windsor Place itself.
The Sanborn sheet also labels a building as “Hefft Memorial Baptist Church.”The Hefft Memorial Baptist Church was a small Brooklyn Baptist congregation; the Windsor Place location was one of its meeting houses. The name “Hefft Memorial” suggests it commemorated a Hefft family donor — a common naming pattern for Baptist meeting houses of the period. This church is no longer extant under this name, indicating that either the congregation moved or was absorbed into a larger Brooklyn Baptist association before mid-century.
The street is fully brick. Sanborn color-codes construction material: pink shading is brick, yellow is wood/frame, blue is stone. The Windsor Place sheet shows pink shading on every single building. By 1906, every house on Windsor Place 1-129 was brick. There were no wood-frame holdouts. This is consistent with the formal post-1888 development pattern of upper-middle-class brownstone construction — Windsor Place was built up tight to its fire-insurance-friendly brick spec.
The street is mostly two-story houses with porches. The Sanborn notes “Porch. Party walls brick filled” on essentially every dwelling. These are attached row houses, each sharing party walls with its neighbors — the construction signature we already documented in the 1900 Riegel deed (“for part of the distance through a party wall”). Standard 23'-by-100' row-house lots, fronting both sides of the street.
Sheet 65 covers addresses 1-129. Sheet 74 picks up at 124 and extends to 171. The Sanborn vol's street index lists Windsor Place across two consecutive sheets. Sheet 74 was also extracted via the same pipeline.
The second extracted sheet covers the eastern continuation of Windsor Place — 25 buildings, also predominantly two-story brick row houses. With three structural exceptions.
The largest exception is the Holy Name of Jesus parish complexat addresses 124, 132, 134, 138, and 140 — five separate Sanborn footprints labeled “SCHOOL OF THE HOLY NAME,” all three-story brick, all connected. The church building itself (“Church of the Holy Name”) is labeled on the same sheet, and a “Hartman's Circle Hotel” appears nearby. The Sanborn's detailed notes record “HEAT: STEAM — LIGHTS GAS” for the school's main building. The Holy Name parish was, and is, the Roman-Catholic parish whose territory covers Windsor Terrace; the fact that the parish school occupied five Windsor Place addresses in 1906 documents how central the institution was to the neighborhood's religious infrastructure.
The second exception is one (1) frame building: 136 Windsor Place. The Sanborn labels it “ICE HOUSE.” A single 1-story wood-frame structure on a 100%-brick block — an attached ice-block storage building for cold service in the era before household electric refrigeration. Tucked into the Holy Name school complex, it was likely the parish's ice service for the school + adjacent church + rectory.
Address numbers visible on Sheet 74 (Holy Name block, addresses 124-171): 124, 132, 134, 135, 136, 137, 138, 139, 140, 141, 143, 145, 147, 149, 151, 153, 155, 157, 159, 161, 163, 165, 167, 169, 171. The 125-131 range (probably the street face occupied by the western edge of the school complex) is not numbered separately.
A higher-resolution second pass on Sheet 65 surfaced a layer of small-business and stable infrastructure on the cross-streets immediately surrounding Windsor Place. These don't appear in our per-house Sanborn list (they're on Seventh Ave, Sixteenth Street, Prospect Park West, etc., not Windsor Pl proper) but they fill in the working-neighborhood context of 1906:
Plus a row of working stables and carriage houses behind the street fronts: 388 Sixteenth St rear(Carriage House 31'x21'), 453 Sixteenth St(Stable & Hay Loft, 2 stories), 198 Fifteenth St(Stable & Hay Loft), and two more on Prospect Park West (202 and 208). The Little Sisters of the Poor complex had its own Wagon House and a labeled “COW PS.”(cow pens) — the institutional farm built into the Catholic home.
Small construction-detail labels visible across the sheet: “BEING BUILT,” “FOUNDATIONS,” “IRON CLAD,” “STONE FLOORS,” “HEAT: HOT AIR · LIGHTS: GAS · POWER: NONE,” “L.P. BLRS” (low-pressure boilers), and water-pipe sizes (8", 12", 20") — the fire-insurance underwriter's utility-spec checklist.
A higher-resolution re-extraction of Sheet 74 reveals a second block of Windsor Place on the same sheet, addresses 180-253. The street numbering jumps from 171 to 180 (the missing 172-179 range is likely cross-street face at the Holy Name complex). 64 buildings are visible on this second block, and the construction pattern is dramatically different from Sheet 65's uniform-brick blocks:
So upper Windsor Place is not the uniform brick row-house block we saw on Sheet 65. The east side is brick-and-mansard; the west side is two-story wood frame. The 1854 founding deed and the 1900 Riegel deed both emphasized brick row-house construction and party walls. By 1906 most of the street follows that spec — but a 30-house run of two-story frame houses on the west side of the 180s-250s blocks remained as a survivor of an earlier, lower-spec construction wave. Their Sanborn yellow-shaded footprints are immediately visible to the eye on the original map.
Also newly visible on the hi-res pass: Hartman's Circle Hotel on this sheet has BOWLING ALLEYS and a BILLIARD HALL labeled in its complex — both 1906 working-class neighborhood-bar amenities. NYC tax blocks visible: 1106, 1107, 1110, 1111, 1114, 1115, 1116.
The Sanborn fire insurance map series for Brooklyn 1904-1908 has sixteen volumes; LoC publishes no master geographic index. Finding the right volume required OCR'ing fourteen volume index maps through Gemini 2.5 Pro at ~$0.20 per call (research/batch_ocr_sanborn.py). Volumes 1-5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16 of the 1904-1908 series and Vol 5 of the 1886-1888 series were probed. Volume 6 (1906) was confirmed as Park Slope / Windsor Terrace. Its index listed Windsor Pl on sheets 65 (addresses 1-129) and 74 (124-253).
Sheet 65 was fetched at 50% resolution (~1MB JPG) from tile.loc.gov and passed to Gemini 2.5 Pro with a structured-JSON transcription prompt requesting per-building material, stories, use, and any owner / business labels. The pipeline is at research/ocr_sanborn_sheet65.py; the structured output at research/sanborn-1906-vol6-sheet65-extraction.json. Gemini self-rated transcription confidence as “high.”
Source: Library of Congress Sanborn Map Collection, sanborn05791_018 (1904-1908 Vol 6, 1906), Sheet 65. Direct page viewer: loc.gov/item/sanborn05791_018/. Image URL pattern: tile.loc.gov/.../05791_06_1906-0065/full/pct:N/0/default.jpg. OCR via Gemini 2.5 Pro on Vertex AI; cost approximately $0.20. The full block-by-block JSON is at research/sanborn-1906-vol6-sheet65-extraction.json.