2 votes

Corbett's Mill Bridge


3/4 View From Northwest

Photo by Joe Elliott, Summer 1995, for HAER

View photos at Library of Congress

BH Photo #123480


The Maquoketa River flows to the southwest in a series of sharp bends through Scotch Grove Township below the town of Monticello in Jones County. A long-term grist and sawmill site was established on that water power by James S. Applegate in 1858. John Corbett joined the firm, obtained ownership by 1868 and added to the sawmill, enlarged the waterwheel and built a blacksmith shop as well. In 1870 he petitioned the Jones County Board of Supervisors to place an iron bridge on the road which crossed the river above his millpond. The Supervisors responded favorably and appropriated $3,000 for a bridge at Corbett's Mill, two thirds of the cost to be borne by the county, and the remainder by local subscription. On 19 January 1871, a committee was appointed to inspect the proposed site and to select a contractor. On 20 April a Mr. Jones, represented Miller, Jamieson & Company of Cleveland, Ohio (later the Buckeye Bridge Company), presented the Supervisors with plans and cost information. Two bridges were ordered form the company, both measured 128 feet in length. The bridges were delivered by rail. The bridge at Monticello was assembled by crews sent by the company, and by 16 November it was announced that Corbett's Mill Bridge would be completed by the following week. The bridge lacks a name plate, and patent or roller markings of any kind. The bridge continued to be identified with the nearby mill site. The mill passed to Samuel Eby in 1875 and remained in that family's hands until 1913. The original bridge was located on a loop road which apparently was first established so as to circle behind the millpond above the dam. A newer road simply cut off this loop, thereby isolating the bridge. The county raod bypassed the bridge in 1958 and the bridge passed into private ownership. It currently adjoins a privately owned picnic area which is on the east river bank [adapted from Jacobsen 1985]


Bowstring through truss bridge over Maquoketa River on Abandoned Road in Scotch Grove
Scotch Grove, Jones County, Iowa
Destroyed by flooding Saturday July 24, 2010
Built 1871; Bypassed by a new road in 1958 and passed into private ownership.
- Buckeye Bridge Works of Cleveland, Ohio
- Miller, Jamieson & Co. of Cleveland, Ohio
"The Corbett's Mill bridge is an example of what was once a common bridge form: the bowstring arch-truss. In the 1860s and 1870s bowstring arch-trusses were used extensively because of their great structural efficiency and relatively low construction costs. During this period many thousands of bowstring arch-trusses were built in the nation. Because the development of Iowa's transportation system coincided with this period, the number of bowstrings built in the state numbered in the many hundreds. Most of these were built by the large Ohio bridge companies, such as the King Iron Bridge and Manufacturing Company, the Massillon Bridge Company, and the Wrought Iron Bridge Company. The Corbett's Mill bridge is an excellent example of a bowstring arch-truss that was built by a smaller company: the Buckeye Bridge Company, also of Ohio.

"This document was prepared as part of the Iowa Historic Bridges Recording Project performed durng the Summer of 1995 by the Historic American Engineering Record (HAER). The project was sponsored by the Iowa Department of Transportation (IDOT). Preliminary research on this bridge was performed by Clayton B. Fraser of Fraserdesign, Loveland, CO."

Historian: Geoffrey H. Goldberg, engineer, August 1995

Span length: 128.0 ft.
Total length: 128.0 ft.
Posted to the National Register of Historic Places on April 11, 1985
Also called
Eby's Mill Bridge
Approximate latitude, longitude
+42.20010, -91.05935   (decimal degrees)
42°12'00" N, 91°03'34" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/660218/4673816 (zone/easting/northing)
Quadrangle map:
Scotch Grove
Inventory numbers
NRHP 85000722 (National Register of Historic Places reference number)
BH 37395 (Bridgehunter.com ID)

Update Log 

  • January 14, 2020: Updated by Tony Dillon: Corrected error as this was a through truss and not a pony.
  • July 26, 2011: Updated by Luke Harden: Added description
  • July 27, 2010: Updated by Nathan Holth: This bowstring has been destroyed by floods.
  • September 10, 2008: Added by J.R. Manning



Corbett's Mill Bridge
Posted March 4, 2019, by Robert Elder (robertelder1 [at] gmail [dot] com)

By the way, I was correcting my own post in the previous comments.

Corbett's Mill Bridge
Posted March 3, 2019, by Tony Dillon (spansaver [at] hotmail [dot] com)

So I see a bridge at this location... My initial excitement that the bridge might have been fished out of the drink and rebuilt was tempered by zooming in on what appears to be a modern welded bowstring-style pony.

Somebody else can make a page for it if they want... I'm not feeling it!

Corbett's Mill Bridge
Posted July 28, 2010, by Robert Elder (robertelder1 [at] gmail [dot] com)

I figured that is what you meant. I was also thinking of bowstrings when I mentioned this bridge being the last through truss built by the company.

The double-tubular vertical members seem to be indicative of a bowstring bridge built by the BBW.

Corbett's Mill Bridge
Posted July 28, 2010, by Anthony Dillon (spansaver [at] hotmail [dot] com)

Sorry, was only thinking Bowstrings when I posted last night. Yes the Charlotte Highway Bridge is a beautiful Whipple truss of the Buckeye Bridge Works that remains in Michigan. Randolph County, Indiana had a smaller Whipple span and some very unique BBW ponies, but all are long gone.

Corbett's Mill Bridge
Posted July 28, 2010, by Robert Elder (robertelder1 [at] gmail [dot] com)

Correction to previous post, there is also a Buckeye Bridge Works span (Whipple Truss) in Michigan:


Regardless, very few representative bridges of any kind, built by this company appear to be extant.

Corbett's Mill Bridge
Posted July 28, 2010, by Robert Elder (robertelder1 [at] gmail [dot] com)

We always lose a few bridges each year due to severe weather, but as all have stated below this is a particularly major loss. Iowa probably has more bowstring trusses than any other state in the USA. The Decorah area is particularly rich in bowstrings.

As far as Buckeye Bridge Works spans, there may be a second one remaining in Kansas. This bridge appears to be a mate to the KSHS example. This would make logical sense as the KSHS bridge was originally a triple span, and the other two spans were reused in Miami County. The bridge was extant in the 1980s, but the status is now unknown.



The Miami County Bowstring, if extant, also appears to be on a private road, much like this Iowa example. This Iowa example may have been the last through bowstring built by this company. Hopefully some salvageable parts can be located.

Corbett's Mill Bridge
Posted July 27, 2010, by Nathan Holth (form3 [at] historicbridges [dot] org)

Two further comments:

1. Some of Iowa's historic truss bridges have been moved off of their abutments and placed on land as a non-functional exhibit. While some people think this is not an optimal solution, I think its a great solution. For all the flooding that goes on in Iowa and how many historic bridges get washed away, its a wonder there is a single historic bridge left in the state. I would argue that when historic bridges are preserved in Iowa, either funding be set in place to raise the bridge to a safe height, otherwise, placing it on land may be the responsible thing to do.

2. Privately owned historic bridges are particularly problematic because their owners often lack the funding to restore the bridges (or raise them up to a safe height). They also likely do not hire trained inspectors to inspect the bridges. Further, traditional funding sources for preservation are not available. Private bridges as such may not be at risk for replacement like public highway bridges, but they are at greater risk for neglect and collapse.

Corbett's Mill Bridge
Posted July 27, 2010, by Anthony Dillon (spansaver [at] hotmail [dot] com)

And to make matters worse it's a rare Buckeye Bridge Works span. To my knowledge, the small bowstring at the Kansas Historical Society is now the last remaining.


Corbett's Mill Bridge
Posted July 27, 2010, by Nathan Holth (form3 [at] historicbridges [dot] org)

The ONE bowstring truss in this region of Iowa I did not visit, and what happens? It is the ONE bowstring that gets destroyed. Sometimes I wonder why I remain interested in working with historic bridges. Working with historic bridges is like living with chronic depression. One disaster after another.