In the 1920s, State Highway 170 followed today's New London Turnpike from Route 32 in Montville to the old Route 2 in Norwich.

20.70 miles; from I-84 in Union to US 44/Route 12 in Putnam.

In the 1920s, State Highway 171 followed today's Route 142 in East Haven.

The old Route 171, commissioned in 1932, ran from Route 14 (now Route 66) in East Hampton to Route 149 in East Haddam, using parts of Main Street, Colchester Avenue (today's Route 16), Waterhole Road and Trowbridge Road.

In 1933 or 1934, Route 16 was created, and Route 171 was shortened to Waterhole and Trowbridge Roads, between 16 and 149. In 1940 or 1941, Route 171 was deleted entirely, and the roads turned over to the towns.

The modern route 171 came into being in 1959, leading from Route 198 at Kenyonville to Route 12 in Putnam. This was formerly part of state route 91, which had to be renumbered to make way for Interstate 91. The stretch of today's Route 171 leading into Union became part of Route 198.

In 1963, Route 198 and Route 171 were reconfigured in Union, Eastford and Woodstock to their present-day locations.

• Route 171 Ends (Photos; Doug Kerr at state-ends.com)

4.45 miles; from I-84 to Route 67 in Southbury.

In the 1920s, State Highway 172 followed today's Route 69 from Waterbury to Bristol

The modern Route 172 was commissioned in 1932; few or no changes since then.

• Route 172 Ends (Photos; Doug Kerr at state-ends.com)

6.17 miles; from US 5/Route 15 in Newington to Hooker Drive (just north of I-84) in West Hartford. The guide signs on I-84 for Exit 41 ("South Main St") don't mention Route 173.

Commissioned in 1932, Route 173 originally extended north along Quaker Lane to meet Farmington Ave (at the time, Route 4) in West Hartford, for a length of 7.47 miles. In 1963, that section was deleted.

• Newington Roads
• Route 173 Ends (Photos; Doug Kerr at state-ends.com)

3.18 miles; from Route 71 in New Britain to Route 176 in Newington. Route 174 is a four-lane boulevard near Route 71 and Route 9.

Commissioned in 1932, and has had few or no routing changes since then.

However, Route 174 was almost deleted from the state highway system in the state's Route Reclassification in 1962. The state wanted to turn it over to the towns, possibly because it paralleled Route 175, another state highway.

The city of New Britain insisted the state retain control, because of the road's "increasing importance in arterial traffic flow of the city." The state countered that Route 174 is a "short leg", and the traffic load was not as heavy as the city contended.

Route 174 even disappeared from a few state maps in the 1960s, which must have pleased city officials. However, it remains in the state highway system to this day, along with several other short leg routes in the area.

Take over Route 287 to Route 3 in Wethersfield. And put a "174" on the Route 9 exit.

• "State Highway Dept. Grants Second Extension." Hartford Courant, Aug. 24, 1962.
• "States Takes Over Roads Controversy Continues." Hartford Courant, Sep. 10, 1962.

• Newington Roads
• Route 174 Ends (Photos; Doug Kerr at state-ends.com)