For a time, Caldwell was known as Hamburg, after Jake Ham established a blacksmith shop here. An early railroad camp for construction employees of the Oregon Short Line Railroad nearby was dubbed Bugtown and the community shared this name as well. Caldwell burst into existence suddenly and grew rapidly with its eleven saloons and a private water pump – an oasis in the desert area of sage and ankle-deep alkali dust.
In August of 1883 the original town site was platted parallel to the Oregon Short Line rail tracks (later to become part of Union Pacific). The property was owned by the Idaho and Oregon Land Improvement Company, which was interested in persuading settlers and businessmen to move here. The group ignored compass and section lines and established the town site in honor of the company’s president, C.A. Caldwell, ex-senator from Kansas.
By January 1884, there were more than 600 residents and 150 structures, 40 business operations, one school, a telephone exchange and two weekly newspapers (the Caldwell Tribune and Caldwell Record) in the community of Caldwell. Two months later there were several churches and social activities including an amateur theatrical group, a skating rink, and the Caldwell Silver Cornet Band. The first circus in 1884 drew from surrounding areas and had 7000 paid admissions. The date of ordinance establishing Caldwell as a city is January 15, 1890. The College of Idaho, a Presbyterian college, was founded in Caldwell in 1891. The college is the oldest institution of higher learning in the state. It continues to be known as one of the best liberal arts colleges in the entire country.
The city was officially chartered by the order of the Ada County Commissioners on January 15, 1890, with its boundaries (six square miles) set around the railroad. On March 7, 1891, Canyon County was created as a separate entity from Ada County, and Caldwell was named the county seat.
For several years during the early 1890's, the Boise Interurban provided electric streetcar service to valley towns including Caldwell. One of the town's greatest periods of growth took place between 1905 and 1908 when the population grew to approximately 5,000 an increase of nearly 4,000 in three years!