The most defensible answer is that no intact IB&O bridge span over the York River could be verified from current public sources. [unverified] The question places the suspected crossing west of Bancroft and asks specifically for maps or photographs of the former bridge. [1] BancroftOntario’s local history page preserves a report that only a few pilings may remain at the river’s edge, but that is a community recollection rather than an engineering survey or current land-access record. [2]

The historical railway context is documented, although the available sources do not align perfectly on the dates. [2][3] Canada-Rail describes an 1886 contract to build the IB&O from Howland Junction to York River on the Central Ontario Railway and later describes the line’s connection at Bancroft under Canadian Northern ownership. [3] BancroftOntario’s history page separately dates the Central Ontario Railway’s arrival in Bancroft to 1900 and says a second IB&O line connected the town in 1903. [2] For that reason, this answer avoids presenting one exact construction or opening date as settled fact. [2][3]

There is a promising photograph lead. [4] The Community Archives of Belleville and Hastings County’s indexed Hastings County Historical Society photo material includes “The Dam and the York River, Bancroft” graphic material and identifies a “railway bridge on right” under catalogue reference HC03634. [4] I could not inspect the underlying image in this research session, so I cannot confirm that HC03634 shows the particular IB&O bridge west of Bancroft rather than another York River crossing. [unverified]

The best next research route is the Community Archives. [5] The Hastings County Historical Society says that many of its photographs and maps have been digitized online. [5] The linked collection includes HC03xxx photographs, map material and postcards that can be searched with “HC03634,” “York River,” “Bancroft,” “IB&O,” “Central Ontario Railway” and “South Baptiste Lake Road.” [6]

So the careful answer is: the bridge appears to have disappeared as an intact structure, with a local report of possible remaining pilings, and there is a catalogue lead for a historical York River/Bancroft railway-bridge image. [2][4][unverified] The exact surviving remains and whether the indexed photograph is the bridge in this question still need confirmation from the archive or a current site/land survey. [unverified] Do not treat old railway alignments, riverbanks or pilings as public access; confirm permission and current conditions before visiting. [unverified]

Sources

1. Ask Bancroft: IB&O railway bridge over the York River
2. Bancroft History 2
3. Irondale Bancroft and Ottawa Railway - Canada-Rail
4. Hastings County Historical Society photo index, HC03xxx
5. Community Archives - Hastings County Historical Society
6. Hastings County Historical Society collections - CABHC