Old Union Community. Originally known as Ferguson Prairie, this settlement grew up around the property of Joseph and Hannah Ferguson who settled here about 1847. Listed on early maps it was named Ivanhoe, the community name changed following the establishment of a Union Church in 1877. The first sanctuary, a one-room structure, was also used as a community center and schoolhouse. The present building was completed in 1913. Classes were conducted here until 1935; the church continues to meet at this site. Annual homecoming memorial services are held each June. - Historical Marker Text. Marker erected 1980. Located off of FM 3371. 1/4 mile South on CR 750.