Mt. Union Church was organized in 1864 under the name Mulberry Hill General Baptist Church. In 1869 the original log building burned, and the congregation rebuilt on the present site and changed the name to Mt. Union. In 1921, thirteen churches were invited from Mt. Union to form Portland Association, making Mt. Union the mother church of two associations. M.J. Bonner, born on Dec. 17, 1825, and died Nov. 21, 1907, organized the Mt. Union General Baptist Church that stands on these grounds. Rev. Bonner is known as the founder of three associations: the Mt. Union, Green River Union, and New Harmony Assoc. of Gen. Baptists.