The Diocese of Chicago covers twenty-two counties located in the northern third of the state of Illinois, stretching from the shores of Lake Michigan on the east, to the banks of the Mississippi River on the west.

Its northern boundary is the state of Wisconsin; the southernmost city is Watseka, Illinois.

When the Diocese of Illinois was split into three in 1877, Chicago maintained the original succession of bishops as its own.

The diocese is far more ethnically diverse than the Episcopal Church at-large.

There are four Hispanic congregations, one of which is located in the near western suburbs of Chicago.