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Understanding groundwater use, both current and historical, is important for understanding the hydrogeology of groundwater systems, and for water planning. The Queensland portion of Australia's Great Artesian Basin (GAB) is managed under the Water Plan (Great Artesian Basin and Other Regional Aquifers) 2017. Methods were developed to estimate current and historical abstractions from the different hydrostratigraphic units of the basin. In the first stage, source aquifers were assigned to ~96,000 bores within the Queensland GAB footprint. Of these, 31,503 bores were assigned directly to the GAB, with other bores sourcing groundwater from units above or below the GAB. In the second stage, current groundwater use for all bores and historic groundwater-use trends were estimated, covering the 115-year period between 1900 and 2015. These estimates took account of periods of inactivity at the bore, the aquifer condition (sub-artesian, artesian), and the nature of discharge (controlled or uncontrolled). The process used publicly available datasets. This paper presents an overview of the methodology and how the estimates were used to support water planning. The current groundwater use from the GAB in Queensland was estimated to be 322 GL/year, which is lower than previous estimates, partly because of improved estimation techniques, the bore capping and piping programs that have been in progress since 1989, and the naturally reducing discharge rates from uncontrolled artesian bores. [ABSTRACT FROM AUTHOR]