Simplify the following text for a Grade 7 native English-speaking person.
Original: Tampa Bay is a large natural harbor and estuary along the Gulf of Mexico on the west central coast of Florida , comprising Hillsborough Bay , Old Tampa Bay , Middle Tampa Bay , and Lower Tampa Bay .
Simplified: Tampa Bay is a bay in St. Petersburg , Florida , USA that spreads trough Hillsborough Bay , Old Tampa Bay , Middle Tampa Bay , and Lower Tampa Bay .