Gannawarra is a rural district 8 km north-west of Cohuna on the road to Koondrook. It is also a shire formed in 1995 by the union of Kerang and Cohuna municipalities.
Gannawarra was a pastoral run taken up by Archibald Campbell in 1844, occupying about 420 sq km adjoining the Murray River north-westerly from the vicinity of Cohuna.
The Gannawarra district was opened up for farm selections in the 1870s. A school was opened in 1877 and a Baptist church – one of the first churches in the Cohuna area – was opened in 1883. There was a private irrigation scheme, supplied by water pumped from a creek, in the 1880s, a forerunner of the extensive Torrumbarry irrigation district later established by the State Rivers and Water Supply Commission. Until rising water tables and inadequate drainage altered soil conditions, there were orchards and market gardens, as well as dairying. A butter factory was established in 1904 and later moved to Koondrook.
Gannawarra school was closed in 1948 upon the establishment of Cohuna consolidated school, and the place name became a dairying district. It was, however, revived in the 2011 census count. Its census populations have been:
On 20 January 1995 the Gannawarra Shire was formed by the union of Kerang borough and most of Cohuna and Kerang shires. Its area is 3736 sq km, extending from Leitchville to Lalbert in the west. Most of its northern boundary is the Murray River and its southern towns include Quambatook and Macorna. The shire's administrative centre is Kerang.
The west of the shire includes the Avoca River which drains toward an extensive lakes region. East of Kerang the landscape is lined with irrigation channels. Gannawarra Shire's census populations have been:
The median age of residents in the shire at the 2011 census was 47 years, compared with 37 for Australia.
Cohuna and Cohuna Shire, Kerang, and Kerang Shire entries