List of impact craters in North America

Columns: Name | Location | Diameter ( km ) | Age ( Ma/millions )
Crooked Creek | Missouri | 7 | 320 ± 80 | Decaturville | Missouri | 6 | < 300 | Des Plaines | Illinois | 8 | < 280 | Flynn Creek | Tennessee | 3.8 | 360 ± 20 | Glasford | Illinois | 4 | < 430 | Glover Bluff | Wisconsin | 8 | < 500 | Haviland | Kansas | 0.015 | < 0.001

Example questions:
Approximately how many years ago was the impact crater created in Tennessee ? | When was the impact crater discovered in Oklahoma ? | What kind of rocks cover the structure of the impact crater that 's in Alaska ? | When was the impact crater found in Indiana discovered ?

Answers:
360 million years ago | 1991 | Permanently frozen Pliocene and Pleistocene rock | 1880