Route 203 is a state highway in eastern Connecticut, running entirely within the town of Windham.

It intersects Route 14 in Windham center about 1.4 miles (2.3 km) from the river crossing.

In Windham center, it joins Route 14 along North Road for about 0.8 miles (1.3 km).

[2] A reconfiguration of US 6 in North Windham in 1954 resulted in Route 203 ending beyond US 6 at the old US 6 alignment (which was now unsigned SR 682) for several years.

This was rectified in 1962 when SR 682 was deleted and Route 203 cut back to end at current US 6.