Burglars stole cash from Workington Town RLFC during an overnight raid on Sunday.
Police are investigating the burglary at the Derwent Park ground, which happened after 8.45pm.
Workington Town had played a match against York City Knights earlier in the day.
A police spokesman said a "quantity of cash" was taken and damage was caused to the inside of the premises.
Anyone with information, or who saw anyone leaving the area of Derwent Park overnight, should contact police on 101, or Crimestoppers anonymously on 0800 555 111.
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