It begins in the city of Hartford at Albany Avenue (US 44), travels north through the towns of Bloomfield, Windsor, East Granby and Suffield until the Connecticut-Massachusetts state line.

Route 187 crosses the Farmington River between the towns of Bloomfield and East Granby.

Route 187 begins at an intersection with US 44 in Hartford and heads north, crossing into Bloomfield.

It the reenters Bloomfield, where it briefly overlaps with Route 189 to form a four-lane freeway.

Route 187 veers off to the north, and crosses the Farmington River into East Granby.

This junction also marks the western end of Route 147, which carries local traffic toward West Springfield.