sentences:  Formed on December 21, 1816, Pike County was the first county formed after Indiana became a state.It was formed from Gibson, Orange and Perry counties, and initially included most of the territory of later Dubois County and portions of the current form of Gibson, Martin, and Warrick Counties.It was named for Zebulon Pike, famous for his Pike Expedition of 1806 – 1807, exploring the southwest portion of the Louisiana Purchase.