Route 218 becomes a partially controlled-access divided four-lane highway for about four miles (6 km) as it runs east through southern Bloomfield.

It continues east for another half mile to end at an intersection with Route 159.

[1] The easternmost 0.60 miles (0.97 km) of Route 218 are designated the Putnam Memorial Highway.

In 1992, Route 218 was extended to its current eastern terminus in preparation for the construction of I-291 from 1992 to 1994.

[2] Route 218 serves the corridor that was to be part of the northwest quadrant of the I-291 Hartford Beltway that was canceled in the 1970s due to environmental and community opposition.