SR 70 begins in Manatee County just south of Bradenton city limits at an intersection with US 41 (Tamiami Trail).

As it continues through the community of Oneco, it crosses the Seminole Gulf Railway's Sarasota Division and Bowles Creek before coming to an intersection with US 301.

Beyond US 301, SR 70 continues east as it leaves the Bradenton area, crossing the Braden River and coming to an interchange with Interstate 75.

SR 70 remains a six lane road beyond Interstate 75 as it runs along the north side of Lakewood Ranch.

SR 70 enters Arcadia along West Oak Street, and it crosses the Peace River and the Seminole Gulf Railway's Fort Myers Division.

As it enters Fort Pierce city limits, SR 70 turns east on Virginia Avenue and continues another 2.5 miles to its eastern terminus at US 1.

[citation needed] The present route of SR 70 was added to the state highway system in the 1920s with three separate designations.

[7] The full cross-peninsular route from US 41 in Bradenton to US 1 in Fort Pierce was redesignated SR 70 in 1945 as a result of the 1945 Florida state road renumbering.

Prior to the 1960s, SR 70 entered Arcadia from the west on a historic Luten arch bridge over the Peace River.