We list 54 museums and historic sites in Illinois that take a Time Travelers membership, across 42 towns and cities. The largest clusters are Springfield, Rockford and Chicago.
Springfield is the busiest single base: 6 of the 54 are within 25 miles of it, so one day out covers 11% of the state list. Another 38 sit more than 100 miles away, and the list spans about 193 miles end to end, so the rest is a second trip rather than a detour.
Because the benefit is built for travel, the states next door are usually where the card earns its keep.