Idalou is on U.S. highways 62 and 82 twelve miles northeast of Lubbock in east central Lubbock County. It grew up around the switch and small depot constructed when the South Plains and Santa Fe Railway was built from Lubbock to Crosbyton in 1911. The origin of the town's name is disputed: it may be derived from the names of early settlers Lou Bacon and his wife, Ida, or from those of Ida and Lou Bassett, daughters of Julian M. Bassett, the vice president of the local Crosby-Bassett Livestock Company. In 1916, when ranchers began selling acreage for cotton and maize farming, Idalou had a blacksmith shop, a grocery store, a one-room schoolhouse, and a few houses. In 1917 a post office opened there with Sara E. Ross as postmistress. A brick two-story school replaced the previous one in 1919. Idalou was incorporated in 1925 and had 538 residents and twenty-eight businesses by 1930. By 1940 it reported 503 residents and thirty-five businesses. From 1960 to 1980 the town's population grew from 1,274 to 2,348. The growth of the community can be attributed to its location in a major growing and marketing center for cotton and sorghum. In 1990 the population in Idalou was 2,074. The population was 2,157 in 2000.