The original Route 184, commissioned in 1932, was a 7.25-mile route in Bloomfield: starting at US 44, it followed Blue Hills Avenue (now Route 187), Park Avenue and Mountain Avenue (most of which is now Route 178) and West Street to end at Route 185. In 1963, this Route 184 was decommissioned, and Routes 187 and 178 got some of the pieces.
Most of the modern Route 184 started in the 1920s as State Highway 311. This route roughly followed present-day 184 from the Thames River to Old Mystic, and present-day Route 201 and Mystic Road (SR 627) to Route 2 in North Stonington.
In 1932, SH 311 was decommissioned and state route 84 was born; instead of going northeast from Old Mystic, Route 84 instead continued east along present-day Route 234 to Pawcatuck. The northeastern part of SH 311 became unposted SR 668 (later, Route 119; and is now part of Route 201). Some maps also show Route 84 following the old SH 311/new Route 201 to Route 2 for a few years, but official state maps do not show this.
Though some of the 1932 alignment is no longer open to traffic, the original Route 84 started at Bridge Street (old US 1) near North Street and today's I-95 Exit 85 offramp. It then followed:
- a street (now gone) heading northeast to Walker Hill Road
- Walker Hill Road and Toll Gate Road
- Gold Star Highway (today's Route 184) to Old Mystic
- Old Mystic Center Road and Main Street to Pequot Trail
- Pequot Trail (today's Route 234) to US 1 in Stonington
Even in the 1920s and '30s, the need was seen for bypass routes to relieve the congested shore route, US 1. Bypasses to the west were built as Route 80 and the Merritt Parkway. East of the Thames River, this role would be given to Route 84.
In 1934, Connecticut and Rhode Island were building their parts of a 10-mile cutoff road from Old Mystic to Hopkinton that would make the trip from New London to Providence 6 miles and 30 to 45 minutes shorter. In North Stonington, a new rotary intersection with Route 2 would be the largest in the state. The intent was to open by December 1934, but the road ultimately opened in August 1935. At this time Route 84 was 16.48 miles long, slightly longer than Route 184 is today.
On Feb. 27, 1943, a new Gold Star Bridge opened across the Thames River (this bridge was replaced again in 1975). Included in the project were freeway approaches on each side, including a short freeway segment for Route 84, leading east from an interchange with US 1 and Route 12. This is the site of the modern-day Route 184 / Route 12 interchange, bypassed by I-95; before I-95 opened, Route 84 was the main route to Providence from New London.
Though the new bridge was critical to the ongoing war effort, relocation of Route 84 to the east in Groton was halted in March 1943 by the War Production Board: the project was a "desirable long-term improvement", but not critical at the moment.
In 1947, Connecticut proposed rerouting US 1 between New London and Providence to CT 84 (now Route 184) and RI 3 -- a more direct route between the cities. Rhode Island declined: it didn't want to remove US 1 from its shore towns, and lose money for four-laning the road there.
Rhode Island countered with a US 1A proposal for the 84/3 route. Connecticut agreed, and it was sent to AASHO. Afterward, it was either rejected or retracted, because US 1A was never posted along the route.
A 1953 State plan called for Route 84 to become a freeway; however, the freeway became Interstate 95 instead.
In 1958, Route 84 was renumbered CT 95, for number compatibility with the completed sections of I-95 elsewhere. That same year, the Rhode Island director of public works accused Connecticut of delaying I-95 work to encourage motorists to stay on the Connecticut Turnpike to US 6 in Killingly and pay more tolls. The Connecticut Highway Commissioner denied this, saying road building priorities were based solely on traffic needs.
In 1964, when I-95 opened in Groton and Stonington, state route 95 was renumbered 184, which it remains to this day. One of the first Hartford Courant articles to mention Route 184 by name discusses the adverse effect of the opening of I-95 on some Route 184 businesses dependent on drive-by business.
"Route 184 Extension"
Present-day Route 184 ends at Route 216, but the original Route 84 continued east into Rhode Island, becoming RI 3. Today, a road still continues into Rhode Island, but ends shortly after crossing a 1930s concrete bridge just east of the state line. On the Connecticut side, it's called the Providence - New London Turnpike (and SR 626). On the Rhode Island side, it's called Route 184 Extension. There's no public access from this road to the rest of Rhode Island without going back into Connecticut.
Circa 2003, Route 184's interchange with Route 12 was reconstructed. The ramps were realigned, and vertical clearance was increased 12'-2" to 16'-3", but the overall geometry of the 5-ramp interchange was unchanged.
In 2018, the interchange with Route 12 was given an exit number: 1. This is noted only in the gore exit signs and not on the guide signs for the exit.