The Diamond Trail was originally part of the Western Stage Company route that existed decades before the advent of the automobile and auto trails system. Based on local historical records for Hinkletown, Iowa, the trail may have existed as early as the 1840s when it is mentioned that the Gold Rush traffic used the trail in 1848.
Stage-coaching began in Iowa about 1838, reached its peak in the 1850s, and continued until about 1874 when the railroads and roads were well established. In 1854, the Western Stage Company became the largest line in Iowa; they operated nearly all the stage traffic on approximately 14 routes originating from Iowa City.
According to the publication Stagecoach Trails in Iowa by Inez E. Kirkpatrick, 1975, J-B Publishing Company, Crete, Nebr., Iowa had two well-known stage coach routes run by the Western Stage Company. The northern route was from the old Indian Trail, later the dragoon trail at Fort Des Moines. The southern route first originated at Iowa City and ended in Des Moines. It was called the Iowa City-Montezuma Road or Diamond Trail. By 1855, the Diamond Trail route extended from the Mississippi River communities of Burlington and Muscatine westward to Fort Des Moines.
Although stagecoach lines were relatively short lived in Iowa, they helped fill a gap between the southeastern Iowa communities along the Mississippi River to the new state capitol in Des Moines. The last of the Western Stage Company coaches went out of service July 1, 1870.
Members of the Diamond Trail Association were very active in the roadway’s maintenance, even prior to registration of the auto route. The association applied to register the route Sept. 23, 1916. The Iowa State Highway Commission (ISHC) approved the registration Dec. 1, 1916.
R.J. Smith served as president of the organization when it was registered. Its secretary, A.C. Heath, handled all negotiations with the ISHC. The association’s principal place of business was Montezuma in Poweshiek County, Iowa.
The Diamond Trail’s route marker was a canary yellow field with an open black diamond printed over it. The markers were already posted before the route was even registered and were familiar with local motorists.
In addition to vowing to maintain their route markers following registration, the group said they would make annual improvements to the road.
During the registration process there was much debate on whether or not the route marker and/or name of the Diagonal Trail could remain due to a similarly named and marked road called the Black Diamond Trail, which was already registered with the ISHC. It was thought that since the two had very similar markers, motorists might become confused and not know which route they were traveling.
In an attempt to resolve the problem, the ISHC sent a letter to the president of the Black Diamond Trail asking their opinion on the matter. The president replied that he shared the commission’s concerns. Despite these concerns, the ISHC approved the registration for the Diamond Trail because the route was already so well established and they had been using the route markers for a number of years, thus it was assumed the two routes were adequately distinguishable.