Interstate 75 (place)

Normally on U.S. interstate highways, the highway keeps a number below 100 (like 75) and bypasses around major cities (or short dead-end branches) are given an extra digit in front (like 375).

I-75 breaks this rule -- in Tampa, Florida, the main I-75 runs to the east of most of Tampa, while 275 runs through Tampa, crosses Tampa Bay and runs through St. Petersburg, and across the bay again before it merges with 75.