The city of Imperial lies within the Sonoran Desert of Imperial County and once was part of the alignment of US Route 99. US Route 99 originally was aligned on Imperial Avenue through the city of Imperial. US Route 99 was realigned immediately east of Imperial Avenue onto a bypass expressway during 1950. US Route 99 would in Imperial would be replaced by California State Route 86 during 1963 when the former was truncated to downtown Los Angeles. The blog cover depicts the original alignment of US Route 99 along Imperial Avenue in the city of Imperial during 1940. US Route 99 can be seen passing through Imperial via Imperial Avenue on the 1935 Division of Highways Map of Imperial County.
The initial draft of the US Route System was approved by the Secretary of Agriculture during November of 1925. The US Route System within California was approved by California Highway Commission (CHC) with no changes recommended which can be seen in January 1926 California Highways & Public Works. US Route 99 is shown departing San Bernardino via LRN 26 towards El Centro via Imperial.
Thusly planned US Route 99 appears on the 1925 Rand McNally Map of California following LRN 26 through Imperial.
The September/October 1928 California Highways & Public Works noted the paving of US Route 99/LRN 26 between Brawley-El Centro had been budgeted during the September California Highway Commission meeting.
US Route 99/LRN 26 can be seen passing through Imperial via Imperial Avenue on the 1935 Division of Highways Map of Imperial County.