Update: Thanks to readers contacting me, I have learned this was a Lithuanian national church of the Roman Catholic Diocese of Belleville. The stylized onion dome would make sense in an Eastern European church such as Lithuania. I revisited the church in the spring of 2019.
I love this Modernist little church right by the interstate in East St. Louis. I believe it was originally an Eastern Orthodox church, as evidenced by the cool Modern interpretation of an onion dome.
This is the Immculate Conception Lithuanian Catholic Church although listed as a chapel today. It’s still the gathering place for many of Lithuanian ?? decent in the St. Louis area. The owners of the large Kassily Funeral Home were at one time members as well as the mother of present US Senator Dick Durbin. The architect is Lithuanian and designed larger facilities in Chicago for the Lithuanian community there. This church dates back to 1895 and many of the men worked in the old National Stockyards nearby.