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.