Westmorland, originally spelled Westmoreland, was laid out in 1910 by the Oakley Company at the center of their 30,000 acre development. Growth was slow at first, but sped up after Westmoreland was linked by a branch railroad to Calipatria in June 1917. By 1920, the town grew to have a Chamber of Commerce and a wide variety of services. At its creation in 1926 US Highway 99 was routed right through the middle of town, increasing business. By 1930, the town was home to 1300. The city was incorporated June 30, 1934 and the extra 'e' was dropped from the name in 1936. Reportedly, Westmorland was also home to illegal gambling and prostitution from the 1920s into the 1950s. The railroad spur was abandoned in 1970, and today little Westmorland has a population of just over 2000.