The Aetna Hose Hook and Ladder Company of Newark was alerted to the fire in the 2800 block of Pulaski Highway, The Wilmington Trap Shooting Association, shortly after 3:00 a.m. Wednesday.
Fire crews arrived with heavy fire and smoke coming from a building and a small shed.
Investigators determined that there were two intentionally set fires, one in a small shed and a second in a building used by the association for a club house.
Officials say fire burned the shed completely and heavily damaged the main building.
Damage estimates are approximately $75,000.
There were no occupants at the time of the fire and no one was injured battling the blaze.
The investigation continues.
Anyone with information in reference to this incident is urged to call The New Castle Division of The State Fire Marshal at 323-5375 or Crimestoppers at 1-800-TIP-3333.
The shooting club was established in 1910 and is one of the longest running.