The Otowi Suspension Bridge was completed over the Rio Grande in 1924. The bridge has a 194-foot span and 10-foot wide timber roadway. A concrete tower was erected at each end to support the cables. Timber stiffening trusses were installed along each side of the roadway representing a major engineering improvement over other suspension bridges constructed in New Mexico.

The Otowi Suspension Bridge was built just upstream from an existing railroad bridge which was used by vehicular traffic when trains were not in sight prior to the construction of the suspension bridge. The new suspension bridge provided unimproved access to the Los Alamos Ranch School and was used to move lumber, sheep and cattle across the Rio Grande. The bridge was also used to carry equipment and materials to government facilities for developing the atomic bomb at Los Alamos. The site of the diner operated by Edith Warner and visited by Robert Oppenheimer, Niels Bohr and other scientists during the early days of atomic research at Los Alamos is located on the west side of the Rio Grande at the bridge.

The Otowi Suspension Bridge was designed by the New Mexico State Highway Engineer James A,. French. Construction was supervised by Lee W. Campbell and the Kansas City Structural Steel Company is known to have supplied at least part of the required materials. The Otowi Bridge was a major engineering achievement for the State Highway Department for the 1920s and it was featured on the cover of the September 1924 issue of the New Mexico Highway journal.

The suspension bridge was by-passed in 1948 when a new steel truss bridge was completed near the site.* The suspension bridge was left in place as a convenient crossing for livestock but it is now unsafe due to the deteriorated condition of its deck. The Otowi Suspension Bridge is the only remaining example of an "engineered" suspension bridge in New Mexico. The site of the bridge and Edith Warner's diner and residence have been included on the national Register of Historic Places.

One of the largest and most impressive bridge structures in the state is the steel arch bridge over Los Alamos Canyon. This bridge connects Los Alamos National Laboratory technical areas with residences and businesses located at Los Alamos townsite. Prior to its construction, the technical areas were reached by way of a looping road which dropped down into Los Alamos Canyon and then back up to the other side. This road was both inconvenient and dangerous due to the steep grades. Under the leadership of Carroll Tyler, Atomic Energy Commission manager of the Laboratory, funds were obtained and the bridge across the canyon was completed in 1951.

The Los Alamos Canyon Bridge is 820 feet in length and consists of a 442.5-foot arch span and six other spans of 62 feet each. At its center point, the bridge is 180 feet above the canyon floor. The bridge is constructed of steel box beams and has a concrete deck which now carries four traffic lanes and a sidewalk.

The designer of the bridge was Finney and Turnipseed of Topeka, Kansas. The bridge was fabricated by the American Bridge Company and erected by Vinson Construction Company of Phoenix, Arizona, at a cost of #850,000. Although this bridge is less that 40 years old, it has been included in the survey as an exception because of its association with the early days of atomic research at Los Alamos, and because of its engineering significance.