Fla. Stat. § 7.29
The boundary lines of Hillsborough County are as follows: Beginning at the northeast corner of section one in township twenty-seven south, range sixteen east; thence east on the north line of township twenty-seven south to the line between ranges twenty-two and twenty-three east; thence south on said range line to the line between townships thirty-two and thirty-three south; thence west on said township line to the south bank of Tampa bay; thence in a direct line to a point midway between Egmont and Passage Keys in the Gulf of Mexico; thence westerly to the boundary of the State of Florida; thence northerly on the boundary of the State of Florida to a point in the Gulf of Mexico due west of the northern shore of Mullet Key; thence due east to a point one hundred yards due west of the northernmost shore of Mullet Key; thence in a line one hundred yards from the shore line around the southern portion of Mullet Key to a point one hundred yards due east of the easternmost shore of Mullet Key; thence due north to a point due east of the northernmost shore of Mullet Key; thence due east to the middle waters of Tampa Bay; thence in a northerly direction through the middle waters of Tampa Bay and Old Tampa Bay to a point where the range line between ranges sixteen and seventeen east strikes said shore; thence north on said range line to the place of beginning.
Fla. Stat. § 7.29