Millmerran Shire, an area of 4521 sq km, and generally 80 km south-west of Toowoomba, was amalgamated with Toowoomba City and six other shires in 2008 to form Toowoomba Regional Council. The Condamine River flowed through its northeast part, and the shire occupied parts of both the Condamine alluvial plain and the more westerly sandy loams of the central and western Darling Downs.

The Millmerran district was prime sheep production country from the days of the early pastoral runs - Cecil Plains (1841), Canning Creek (1840) and Yandilla (1841) - and was bypassed by the westwards railway lines from Toowoomba that were opened in 1868 (Dalby) and Inglewood (1907). Its two main towns, Millmerran and Cecil Plains, had insignificant population numbers in 1900.

Resumption of part of the Yandilla estate in 1881 led to the development of Millmerran village, but the Cecil Plains estate remained intact until 1916. Within a few years many things changed: Millmerran Shire (along the neighbouring Pittsworth Shire) was formed by severance from Jondaryan Shire in 1913; and the railways were extended from Pittsworth to Millmerran (1911) and from Oakey to Cecil Plains (1919). Prickly pear overran the south-west of the shire, but its eradication and clearing of the scrubland opened up dairying country in the early 1930s. Small dairy factories in Millmerran were replaced by a large co-operative (1934-78). There were also extensive sheep, meat cattle and grain growing areas. Cotton was grown in the Central Downs, and there is a large cotton gin at Cecil Plains. In 1949 the shire was described as follows in the Australian Blue Book:

In 1993 the shire had 92,000 sheep and lambs, 42,000 beef cattle, only 135 dairy cattle and 31,000 pigs. Legumes, cotton and other field crops were grown on 10,000 ha, much of the land being irrigated. An open cut coal mine and power station 12 km south of Millmerran were opened in 2003.

Millmerran Shire's census populations were:

Census DatePopulation
19211658
19473010
19763309
20013898
20063094
Further Reading: 

N.E. Delaney, Millmerran Shire handbook, Brisbane, Queensland Department of Primary Industries, 1970

Cecil Plains and Millmerran entries