In the 1920s, State Highway 134 followed today's US 7 between Canaan and New Milford. (US 7 at that time went into New York along NY 22... strange).

The "modern" Route 134, commissioned in 1932, followed today's Route 109, between Route 25 (today's US 202) and Route 47, for a length of 6.10 miles. Over the next 24 years, it slowly disappeared:

• 1941: stops appearing on most oil company maps
• 1949: disappears from official state highway maps
• 1956: cancelled, and replaced by unsigned SR 857

The state's 1961 route reclassification brought Route 134 back, even better than before. In 1962, Lakeside Road in Morris became SR 706. In 1963, the Bantam Lake Road segment of Route 109 became Route 209; and Route 109 was extended west along SR 706 and SR 857 (former Route 134).