Historic Bridges of Michigan and Elsewhere
Nathan Holth offers information, photographs, and maps for historic bridges, particularly metal truss bridges in the United States and Canada, notably Michigan and Ontario.
http://www.historicbridges.org/

Berlin Iron Bridge Company
Fabricator of metal-truss bridges in the 19th century. Features history, the Company's patented lenticular truss, and list of remaining Berlin bridges in Connecticut.
http://www.past-inc.org/bibco/

Bridges to the Past: Alabama's Covered Bridges
Public TV program featuring Alabama's historic covered bridges.
http://www.alabamatv.org/bridges/

NRS AS
NRS AS - Bridge Building Equipment
http://www.nrsas.com/

Covered Bridges of Maine
The Department of Transportation presents a history of the state's covered bridges and a tour via clickable map: photographs and information on the 9 surviving bridges.
http://www.maine.gov/mdot-stage/covered-bridges/wooden.php

Central Denver Ironworks, Inc.
Custom made fabricator of steel shelters, steel structures, ornamental iron, bridges and steel sculptures.
http://www.cdironworks.com

Bridges 1893 - 1999
A timeline gallery of bridges designed by the HNTB Corporation.
http://bridges.hntb.com/3_time.htm

Bridges - Christchurch City Libraries
These images of early Christchurch and Canterbury have been digitised from the collections of Christchurch City Libraries. They have been sourced from newspapers, archives, books, reports and donations from private collections.
http://library.christchurch.org.nz/heritage/Photos/Bridges.asp

Bailey Bridges Inc.
Specializing in prefabricated steel panel bridges for over 50 years.
http://www.baileybridge.com/

Iranian Bridges
Images and brief text of the 17th-century Sio-Seh and Khaju bridges.
http://tehran.stanford.edu/imagemap/bridge.html