Belle Plain. First official county seat of Callahan County, 1877-1883. The first unofficial county seat was Callahan City where the commissioners court was organized, July 30, 1877, and several civil and probate cases filed by an invalid election, October 13th, and a valid election, December 9, 1877 Belle Plain was selected. On January 16, 1883, the county seat was located at Baird. #360