[2] As the Ohio Department of Transportation (ODOT) built Interstate 275 through Clermont County in the late 1970s, a cloverleaf interchange was graded just south of Milford in preparation for a direct connection to a relocated U.S. Route 50.

The new route would have bypassed Milford, running 7.5 miles (12.1 km) to Fairfax along the northern banks of the Little Miami River and its East Fork.

[3] The relocation was ultimately rejected due to environmental concerns, objections by Terrace Park village officials, a lack of funds, and a decreased demand for the interchange following the completion of the Appalachian Highway (State Route 32), which connected to I-275.

[10] In the early 1990s, a $1.3 million access road, which corresponds to the present-day SR 450, was built from the I-275 interchange directly into the Park 50 TechneCenter entrance on U.S. 50.

[15][16] The parkway's route had been shifted to avoid a series of archaeological sites associated with the Ohio Hopewell people.

After excavation, Miami Township officials discovered that the land may have contained unmarked graves of Black people from the late 1800s and early 1900s.