Connecticut Route 8

Route 8 is a 67.36-mile (108.41 km) state highway in Connecticut that runs north–south from Bridgeport, through Waterbury, all the way to the Massachusetts state line where it continues as Massachusetts Route 8. Most of the highway is a four-lane freeway but the northernmost 8.8 miles (14.2 km) is a two-lane surface road.

Route 8 begins at Interstate 95 (I-95) exit 27A in Bridgeport. The first 3.75 miles (6.04 km) through Bridgeport runs concurrently with the freeway portion of Route 25. Approaching the split between Routes 8 and 25, the road expands to six, eight, and even ten lanes. Route 8 continues northeastward into Trumbull where there is an interchange with the Merritt Parkway.

From Trumbull, it briefly enters Stratford before entering Shelton passing by several exits providing access to business parks. It then crosses the Housatonic River and continues into Derby. After the Route 34 interchange, the road takes on more of a semi-rural character as it winds its way along the Naugatuck River through the towns of Ansonia, Seymour, and Beacon Falls before it becomes more suburban in nature in Naugatuck and then more urban as it enters Waterbury. In Waterbury, Route 8 meets with I-84 at the interchange known locally as the "Mixmaster". After the Route 73 interchange, the road returns to its winding semi-rural nature, passing through Watertown and Thomaston. In the latter city, U.S. Route 6 (US 6) briefly overlaps for about a mile. The highway then continues through Litchfield and Harwinton. After a brief suburban section through Torrington where it intersects US 202 and Route 4, it returns to a rural freeway before entering the town of Winchester.

The freeway section of Route 8 ends at US 44 and Route 183 in Winsted. After a short 0.33-mile (0.53 km) northwesterly overlap with US 44 and Route 183, Route 8 continues north as a mostly rural surface road. It intersects the western end of Route 20 on the northern edge of town, and continues through Colebrook to the Massachusetts state line, becoming Massachusetts Route 8 upon entering Sandisfield.

The section from I-95 to the Route 25 split is also known as the Colonel Henry Mucci Highway (designation continues on Route 25). The section from Shelton to Beacon Falls is known as the General Samuel Jaskilka Highway. The section from Constitution Boulevard in Shelton to Route 334 at the Seymour–Ansonia town line is known as the Ansonia–Derby–Shelton Expressway. The section from Waterbury to the freeway end in Winchester is known as the James H. Darcey Memorial Highway.

Most of the alignment of Route 8 was part of an improved toll road known as the Waterbury River Turnpike, which ran from Naugatuck, via Torrington, Winchester Center and Colebrook Center, to the Massachusetts state line. The turnpike was chartered in 1801 and collected tolls until 1862. Two other sections of Route 8 were also old turnpikes: the portion north of Torrington was known as the Still River Turnpike chartered in 1815; the portion between Seymour and Naugatuck was known as the Humphreysville and Salem Turnpike chartered in 1825.

In 1922, the six New England states began a region-wide highway numbering system. The trunk highway from Stratford through Waterbury to the Massachusetts state line became part of the multi-state New England Route 8. Route 8 remained unchanged in the 1932 state highway renumbering. The main road connecting Bridgeport and Shelton (following Noble Avenue, Huntington Turnpike, Shelton Road, Bridgeport Avenue, and Center Street), which was designated as State Highway 316 in 1922, was renumbered as Route 65 in the 1932 renumbering.

In 1951, the Ansonia–Derby–Shelton Expressway portion between Constitution Boulevard in Shelton and Pershing Drive in Derby (including the Commodore Isaac Hull Memorial Bridge) opened to traffic. As part of the freeway upgrades to Route 8, the southern terminus was shifted west from Stratford to Bridgeport, taking over old Route 65. The original southern end of Route 8 was assigned to an extended Route 110. By 1957, the entire length of the Ansonia–Derby–Shelton Expressway portion was open, with the extension from Pershing Drive to Route 334 at the Ansonia/Seymour town line complete.