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Mason Road - Thornapple River Bridge


Mason Road - Thornapple Creek Bridge

Battle Creek Enquirer: August 12 1956


BH Photo #450903


Was reopened after a two year closure to use as a detour while the Ionia Road Bridge was being built


Lost Pratt pony truss bridge over Thornapple River on Mason Road
Eaton County, Michigan
Replaced by a new bridge
Unknown build year, closed ca. 1953-56, possibly not replaced until 1989?
5-panel, pinned Half-hip Pratt pony truss
Approximate latitude, longitude
+42.61742, -85.05434   (decimal degrees)
42°37'03" N, 85°03'16" W   (degrees°minutes'seconds")
Approximate UTM coordinates
16/659570/4720165 (zone/easting/northing)
Inventory number
BH 85700 (Bridgehunter.com ID)


Eaton County, Michigan (30)
Half-hip Pratt pony truss (601)
Lost (30,055)
Lost 1989 (194)
Lost during 1980s (1,569)
Michigan (1,428)
Owned by county (21,724)
Pony truss (17,240)
Pratt pony truss (4,026)
Pratt truss (10,545)
Replaced by new bridge (20,457)
Truss (36,816)

Update Log 

  • April 5, 2020: Updated by Mike Kerkau: Corrected location
  • June 26, 2019: Updated by Mike Kerkau: History timeline
  • June 26, 2019: Updated by Tony Dillon: Added truss type
  • June 26, 2019: Added by Melissa Brand-Welch


  • Mike Kerkau - mjkerkau [at] gmail [dot] com
  • Melissa Brand-Welch - melissabrandwelch [at] msn [dot] com
  • Tony Dillon - spansaver [at] hotmail [dot] com


Mason Road - Thornapple Creek Bridge
Posted April 5, 2020, by Mike Kerkau (mjkerkau [at] gmail [dot] com)

I'm thinking this is pinned in the wrong place, though so too is its entry on BridgeReports, because the county probably has it mis-labeled.

They have it as crossing Thornapple "Creek", but looking at both the satellite and old aerials of the location...neither shows a bridge. Go up the road to where it's clearly the Thornapple RIVER, on the other hand...

As there is only one entry for Mason Road at all, it's probably the river crossing at 42.617415,-85.05434. 1955 easily gives the best image there.

Mason Road - Thornapple Creek Bridge
Posted June 27, 2019, by Tony Dillon (spansaver [at] hotmail [dot] com)

I just want to commend Melissa for the outstanding job that she is doing adding all of these long lost spans that we might otherwise have never known existed!

I also want to remind us all how much things change over the course of 40 or 50 years... Or more. Road names and alignments change, and I have seen old roads virtually disappear. And even more important is just how inaccurate these newspaper articles can be about the where; when; and how. It is our jobs to help add to this information and change things when we have solid details that prove something as incorrect. People that live in a particular state that she has added to might have a better perspective about a bridge's former location or history. But I would ask us all not to be critical of the work she is doing because I know that she is doing her best. It takes a special skill to glean through old newspapers for hours and not go cross-eyed... A talent I do not possess!

Keep up the good work Melissa!

Mason Road - Thornapple Creek Bridge
Posted June 27, 2019, by Melissa Brand-Welch (melissabrandwelch [at] msn [dot] com)

Thanks Mike. I couldn't find any information on a replacement prior to 1989. But I'll keep looking...

Mason Road - Thornapple Creek Bridge
Posted June 26, 2019, by Mike Kerkau (mjkerkau [at] gmail [dot] com)

Hmmm. Per the NBI, this location's replacement wasn't built until 1989, which I'd be a bit skeptical of at first if only for the fact that this was closed for two years in the mid-50s, as the article says.

Then again...it also gives an ADT of only 80 for the road back in 1991, and that's only up to 727 today. So, given the low traffic volumes - maybe this did survive that long past the 50s?

Mason Road - Thornapple Creek Bridge
Posted June 26, 2019, by Melissa Brand-Welch (melissabrandwelch [at] msn [dot] com)

Thanks Tony!