The extension begins at its southern terminus at U.S. Route 1 (US 1) in Florida City, and transitions into the SR 91 mainline in Miramar at its northern end.

It was opened in stages between 1973 and 1974, after the mainline of the Turnpike was completed, and is used by both commuters and travelers to the Florida Keys and Everglades National Park.

Travelers to here from the northern parts of the Turnpike Extension can continue south along US 1 to the Florida Keys or the Everglades National Park (via SR 9336).

Continuing north, the HEFT serves SR 994 (Quail Roost Drive) at exit 13 and gains another lane in each direction.

This is followed by SR 992 (Coral Reef Drive (Southwest 152nd Street)) at exit 16, which marks the northern terminus of the John F. Cosgrove Highway.

Between exits 16 and 17, the Turnpike Extension swells to ten lanes; this section of the tollway also has the highest traffic count at 172,000 vehicles per day (as of 2014).

Just north of the Southwest 120th Street exit, still at mile 19, lies the Snapper Creek Service plaza, which is located on the center median with access from both directions and is the only plaza on the extension; unlike the more robust services along the mainline, it only offers a convenience store inside the gas station.

It crosses the Broward County line, entering the suburban community of Miramar,[13] and then curves eastward.

The expressway has an interchange with SR 823 (Red Road) at exit 43, after which the Turnpike Extension is just one block north of the Miami-Dade County line for the remainder of the tollway's length.

[15] As of July 1, 2015, the total cost for a two-axled vehicle to drive the whole length of the Turnpike Extension is $4.24 with SunPass and $5.28 via the toll-by-plate system.

[20] The northernmost thirteen miles of the tollway between US 27 and the Turnpike mainline was open to traffic on May 1, 1973, at a cost of $22 million and a $0.40 toll to motorists.

[21] During the first half of 1974, the expressway between Campbell Drive (SW 312th Street) and US 27 was opened in five stages, with the road running uninterrupted from the Turnpike in Miramar to Homestead on May 20, 1974, with the last section to Florida City connecting to US 1 completed later in 1974.

[29][30] In 1997, the Bird Road toll plaza was reconfigured to a two part form to accommodate the then-bottleneck section of the expressway.

[33][34] The portion of the HEFT between Exits 11 (Cutler Ridge Boulevard) and 16 (State Road 992) was designated the "John F. Cosgrove Highway" in 2008 by the Florida Legislature, following his death in 2006.

[10][17] Construction was completed in 2018 on a project to add Express Lanes from Eureka Drive to the DOn Shula Expressway.